Although the megapixel race has been going on since digital cameras had been invented, the last few years in particular have seen a huge increase in resolution – we have seen everything from 41 megapixel camera phones to now 50.6 megapixel full-frame DSLR cameras. It seems like we have already reached the theoretical maximum for handling noise at high ISOs with the current generation sensor technology, so the manufacturers are now focusing their efforts in packing more resolution, while keeping sensor sizes the same in order to lure more customers to upgrade to the latest and greatest. In this article, I will try to explain some basic terminology in regards to resolution and hopefully help our readers in understanding camera resolution better.
Before we get started, let’s first talk about what resolution impacts and then we will address some of the common misconceptions.
1) Camera Resolution: What it Affects
In digital photography, camera resolution is associated with a number of different factors:
- Print Size – usually the most important factor. Basically, the more resolution, the larger the potential print size. Printing from digital images is accomplished by squeezing a certain number of Pixels Per Inch (PPI). A high quality print with good details usually involves printing at around 300 PPI, so the size of the potential print is calculated by taking image width and height and dividing them by the PPI number. For example, a 12.1 MP resolution image from the Nikon D700 has image dimensions of 4,256 x 2,832. If you wanted to create a high quality print with lots of details at 300 PPI, the print size would be limited to approximately 14.2″ x 9.4″ print (4,256 / 300 = 14.2 and 2,832 / 300 = 9.4). Larger prints would be possible, but they would require you to either drop the PPI to a lower number, or use special third party tools that use complex algorithms to upscale or “up-sample” an image to a higher resolution, which do not always yield good results. In short, higher resolution is usually more desirable for the ability to print larger.
- Cropping Options – the higher the resolution, the more room there is to potentially crop images. Although many photographers avoid heavy cropping, sometimes it is necessary to focus on the desired subject(s). For example, sports and wildlife photographers often resort to cropping, because they might not be able to get closer to action, but at the same time do not want their final images to contain unnecessary clutter surrounding the main subject(s). As a result, they often employ heavy cropping, which ultimately reduces resolution, which is why they tend to desire as much resolution as possible and practical.
- Down-sampling – as I have previously explained in my article on the benefits of high resolution sensors, the higher the resolution, the better the options for resizing or “down-sampling” images. As I will explain further down below, modern high resolution cameras have similar performance as their lower resolution counterparts, but their main advantages are the ability to down-sample to lower resolution to decrease the amount of noise and when shooting at low ISOs, the ability to yield larger prints.
- Display Size – during the past 10+ years, we have seen a significant progress is display technology. Monitors, TVs, projectors, phones, hand-held and other devices have seen big increases in resolution and the increased space on those devices naturally led to the need to show higher resolution images with more details. 4K monitors and TVs (over 8 megapixels) are getting more popular and common, which puts more burden on cameras to yield images with enough details to showcase on such high resolution devices.
Judging from the above, it seems like higher resolution is always better. But that’s certainly not the case, because it is not just about the quantity of pixels, but their quality. Further down below, I will explain what this means in regards to sensor size, pixel size, lens resolving power and technique.
2) Camera Resolution: How Much More is X MP vs Y MP?
When Nikon first introduced its D800 / D800E cameras with 36.3 MP resolution full-frame image sensors, many photographers were still shooting with 12.1 MP full-frame cameras like Nikon D700 and D3 / D3s. Doing simple math, many claimed that the 36.3 MP sensor represented 3 times more resolution (12.1 MP x 3 = 36.3 MP) and some wrongfully assumed that upgrading to a camera like D800 would yield 3 times bigger prints. While the total number of effective pixels indeed is three times larger when comparing 36.3 MP vs 12.1 MP, the difference in linear resolution is actually far smaller. That’s because sensor resolution is calculated by taking the total number of horizontal pixels and multiplying it by the total number of vertical pixels, similar to how you calculate the area of a rectangle. In the case of the D700, which has an image size of 4,256 x 2,832, the sensor resolution equals 12,052,992, which rounds to approximately 12.1 megapixels. If we look at the Nikon D800, its image size is 7,360 x 4,912 and hence the sensor resolution is 36,152,320, roughly 36.15 megapixels (the discrepancy between 36.15 vs 36.3 comes from the fact that some of the pixels, such as optical black and dummy, around the edges of the sensor are used to provide additional data).
Now if we compare the total number of horizontal pixels between the D700 and the D800, it is 4,256 vs 7,360 – an increase of only 73%, not 200% as wrongfully assumed by many. What does this translate to? Basically, if you could print a detailed 14.2″ x 9.4″ print at 300 PPI with the D700, upgrading to the D800 would potentially result in a 24.5″ x 16.4″ print at the same 300 PPI. Hence, moving up from 12 MP to 36 MP would translate to 73% and not 3x larger prints. Again, it is easy to confuse total area with horizontal width, so it is important to understand the difference here.
In order to yield twice larger prints at the same PPI, you would need to multiply sensor resolution by 4. For example, if you own a D700 and you are wondering what kind of sensor resolution you would need to print 2x larger, you multiply 12.1 MP (sensor resolution) x 4, which translates to a 48.4 MP sensor. So if you were to move up to say the latest Canon 5DS DSLR that has a 50.6 MP sensor, you would get prints a bit larger than 2x in comparison. To understand these differences in resolution, it is best to take a look at the below comparison of different popular sensor resolutions of modern digital cameras from 12.1 MP to 50.6 MP:
As you can see, despite the fact that sensor resolution numbers increase significantly when going from something like 12.1 MP to 50.6 MP, the actual difference in horizontal width is much less pronounced. But if you were to look at the total area differences, then the differences are indeed significant – you could take 4 prints from the D700, stack them together and still be short when compared to a 50.6 MP image, as shown below:
Keep all this in mind when comparing cameras and thinking about differences in resolution.
3) Sensor Size, Pixel Size and Differences in Resolution
As you may already know, sensor resolution is far from being the most important camera feature and a lot of that has to do with the physical size of the camera sensor and its pixels. You might see two cameras with the same resolution, but one might have a sensor that is significantly larger than the other. For example, the Nikon D7100 has a 24.1 MP sensor, while the Nikon D750 has a 24.3 MP sensor – both have similar sensor resolution. However, if you look at the physical sizes of sensors on the two, the Nikon D7100 has a sensor size of 23.5 x 15.6mm, while the sensor on the Nikon D750 measures 35.9 x 24.0mm – 52% larger in linear width or 2.3x larger in total sensor area. What does this mean? Despite the fact that both cameras yield images of similar width (6000 x 4000 on the D7100 vs 6016 x 4016 on the D750), the physical size of each pixel on the D750 sensor is 52% / 1.52x larger in comparison. That’s how the two cameras are able to have similar resolution and hence can potentially make similar size prints (more on this below).
If we divide sensor width by image width, we can calculate the approximate size of each pixel. In the case of the D7100, taking 23.5 and dividing by 6000 yields approximately 3.92 µm, while dividing 35.9 on the Nikon D750 by 6016 yields approximately 5.97 µm pixel size.
So what difference does pixel size make in images? In essence, larger pixels can collect more light than smaller pixels, which translates to better image quality and handling of noise per pixel. However, there are a few caveats you need to keep in mind:
- Differences are small when there is abundance of light (low ISO levels) – if shooting close to base ISO such as ISO 100-400, there is usually little difference in noise performance between pixels (for up to 2x pixel size differences, but not larger). In the case of D7100 and D750, both yield practically noise-free images from ISO 100 to 400. However, there is a noticeable difference in performance at higher ISOs starting from ISO 800, in D750’s favor. So larger pixels tend to be more suitable for low-light environments where higher ISO levels will often be used.
- If sensor size is the same but resolution is different, smaller pixels do not necessarily translate to more noise – a sensor with more resolution means you could print larger. Since noise is usually not evaluated on a per-pixel basis, but rather on equivalent print sizes, you would have to print at the same size to evaluate noise from two different resolution sensors. For example, the Nikon D750 has a 24.3 MP sensor, while the newer Nikon D810 has a 36.3 MP sensor. Since the D810 has more resolution, its pixel size is noticeably smaller than on the D750 (4.88 µm vs 5.97 µm), which means that it is expected to see more noise if you zoom in to 100% view. However, if we were to make equivalent size prints from both, we will have to resize images from the D810 to match the print size of the D750 by reducing 36.3 MP to 24.3 MP, which at the same print size would show similar noise. Take a look at the below images from both cameras, with the D810 image resized to 24.3 MP (left: Nikon D750, right: Nikon D810, ISO 1600):
As you can see, both images look pretty similar in terms of noise, although the D810 is technically supposed to have more noticeable noise due to having smaller pixels. If I replaced the D750 with the 16 MP Df or D4s, the resulting images would look similar at 16 MP.
Given the above, how would an image from the 38 MP Nokia 808 PureView camera phone compare to an image from the 36.3 MP Nikon D810 full-frame DSLR camera? Well, there is simply no comparison, as we are talking about a small sensor measuring 13.3 x 10.67mm on the phone, versus a 35mm DSLR sensor measuring 35.9 x 24mm – a difference of 270% in sensor width or 6x in total area. So despite the fact that the Nokia 808 has technically more resolution than the D810, its pixel size is a puny 1.4 µm compared to 4.88 µm on the D810, which will make images from the phone camera look like mud when compared to images from the D810. Although the Nokia 808 PureView can potentially make larger prints, the D810 will obviously produce much better quality prints with more detail, because the overall camera system is capable of taking advantage of the full 36.3 MP sensor, whereas the Nokia phone’s real resolution is much worse in comparison. This shows that there is much more to resolution and printing than just pure megapixels. Let’s now jump to Lens Sharpness and Lens Resolving Power.
4) Lens Sharpness / Resolving Power
Big megapixel numbers on the sensor are useless, if the lens is too poor to resolve enough detail to provide data for each pixel on the sensor. The same Nokia 808 PureView might have 38 MP resolution, but how much detail can it actually show at pixel level when compared to the 36 MP D810 with a solid full-frame lens attached to it? Not a whole lot. So its real performance in terms of resolution is far less than 38 MP, actually closer to 5 MP in comparison, maybe even less. It makes sense, because you cannot compare a small sensor camera with a tiny lens to a full-frame DSLR and a high-end lens with amazing resolving power. Another problem is diffraction – smaller sensor cameras will be diffraction-limited at much larger apertures, which will also effectively reduce sharpness and effective resolution.
When comparing same size sensor cameras with different resolutions, you have to keep in mind that the camera with more resolution will always put more strain on the lens in terms of resolving power. A lens might do quite well on a 12 MP camera, but fail to resolve enough details on a 24 MP or a 36 MP camera, essentially throwing away the high resolution advantage. In some cases, you might be better off not moving up to a higher resolution camera to deal less with other issues, such as the need for more storage and processing power.
Although manufacturers like Nikon and Canon have been actively releasing lenses specifically designed for higher resolution sensors, you might have to re-evaluate every lens purchased in the past to see which ones will provide adequate resolving power for the high resolution sensor and which ones will need to be replaced. In many cases older lenses will suffer from poor mid-frame and corner performance, which might not be desirable for certain types of photography such as landscapes and architecture.
5) Technical Skill
You might have the highest resolution camera on the market and the best lens that is able to take a full advantage of the sensor and still end up with poorly-executed images that lack detail to make good quality prints. Aside from being able to take advantage of good light and carefully frame / compose the scene, you also need to have good technical skills to yield tack sharp images. High resolution cameras essentially “amplify” everything greatly, whether it is camera shake caused by poor hand-holding technique, shutter vibrations originating from the camera, poor focusing technique, unstable tripod, slight wind or other various causes of blur in images.
So if you do decide to move up to a much higher resolution sensor, you might need to spend some time learning proper technique to capture images. You might have to re-evaluate your minimum shutter speed for hand-holding, use of tripod, use of live view for critical focus, use of lenses and optimum apertures and more. Because if you don’t, you might be wasting the potential of your camera sensor…
In the next article, we go over the question on how much resolution you truly need, by analyzing existing data and going over other considerations in regards to moving up in camera resolution.
Hi, Nasim,
Thank you for the great article again. I wanted to ask a question that is slightly off topic. Since electronic shutters do not produce vibration, why don’t the camera makers switch from mechanical shutter to the electronic ones completely? There are must be a reason.
Thank you again,
Val
Electronic shutters read the image sensor line by line and are slower. This causes problems when the subject is moving, when you’re panning the camera or when shooting under fluorescent light.
Thank you, Alfredo,
Alfredo, you talk here about electronic rolling shutter that actually works very similar to mechanical shutter, it does not capture image at one time but scans the sensor. But with electronic global shutter you capture image at one time (no scanning here). Also, in general electronic shutter can easily be much faster than mechanical one…
Real World Digital Photography
Digital Photography Fundamentals: Understanding Resolution and Bit Depth
Adapted from Real World Digital Photography, 3rd Edition (Peachpit Press)
By Katrin Eismann, Sean Duggan, Tim Grey
PPI vs. DPI
Purists will draw a careful distinction between ppi and dpi. Pixels are the dots on your monitor, and dots are, well, the dots on paper. The distinction between the two is subtle, but we feel it’s important to use the most clear and accurate terminology. Therefore, we use the term ppi when referring to pixels on a digital camera or display device and dpi when referring to dots in printed output.
If you hear people using dpi as a general term for resolution, understand that they may mean ppi when they say dpi (and then recommend that they buy and read this book!).
Resolution is one of the most important concepts to understand in digital imaging and especially in digital photography. The term resolution describes both pixel count and pixel density, and in a variety of circumstances these concepts are used interchangeably, which can add to misunderstanding.
Camera resolution is measured in megapixels (meaning millions of pixels); both image file resolution and monitor resolution are measured in either pixels per inch (ppi) or pixel dimensions (such as 1024 by 768 pixels); and printer resolution is measured in dots per inch (dpi) (see below). In each of these circumstances, different numbers are used to describe the same image, making it challenging to translate from one system of measurement to another. This in turn can make it difficult to understand how the numbers relate to real-world factors such as the image detail and quality or file size and print size.
Different devices use different units for measuring resolution, which can cause some confusion for photographers. Understanding how resolution is represented for each device will help you better understand the capabilities of each in your workflow.
The bottom line is that resolution equals information. The higher the resolu- tion, the more image information you have. If we’re talking about resolution in terms of total pixel count, such as the number of megapixels captured by a digital camera, we are referring to the total amount of information the camera sensor can capture, with the caveat that more isn’t automatically better. If we’re talking about the density of pixels, such as the number of dots per inch for a print, we’re talking about the number of pixels in a given area. The more pixels you have in your image, the larger that image can be reproduced. The higher the density of the pixels in the image, the greater the likelihood that the image will exhibit more detail or quality.
The biggest question to consider when it comes to resolution is—How much do I really need? More resolution is generally a good thing, but that doesn’t mean you always need the highest resolution available to get the job done. Instead, you should match the capabilities of the digital tools you’re using to your specific needs. For example, if you are a real estate agent who is using a digital camera only for posting photos of houses on a Web site and printing those images at 4 by 6 inches on flyers, you really don’t need a multi-thousand- dollar, 22-megapixel digital camera to achieve excellent results. In fact, a 4–6-megapixel point and shoot camera would handle this particular need, although having more image information would be beneficial in the event you needed to crop an image or periodically produce larger output.
Megapixels vs. Effective Megapixels
Digital cameras are identified based on their resolution, which is measured in megapixels. This term is simply a measure of how many millions of pixels the camera’s image sensor captures to produce the digital image. The more megapixels a camera captures, the more information it gathers. That trans- lates into larger possible image output sizes.
However, not all the pixels in an image sensor are used to capture an image. Pixels around the edge are often masked, or covered up. This is done for a variety of reasons, from modifying the aspect ratio of the final image to measuring a black point (where the camera reads the value of a pixel when no light reaches it) during exposure for use in processing the final image. Because all pixels in the sensor aren’t necessarily used to produce the final image, the specifications for a given camera generally include the number of effective megapixels. This indicates the total number of pixels actually used to record the image rather than the total available on the image sensor.
Where Resolution Comes into Play
Resolution is a factor at every step of the photo-editing process. The digital camera you use to record the scene, the monitor you use to view those images, and the printer you use to produce prints all have a maximum resolution that determines how much information they are able to capture, display, or print. Understanding how resolution affects each of these devices will help you determine which tools are best for you and how to use them.
Camera Resolution
Camera resolution defines how many individual pixels are available to record the actual scene. This resolution is generally defined in megapixels, which indicates how many millions of pixels are on the camera sensor that is used to record the scene. The more megapixels the camera offers, the more information is being recorded in the image.
Many photographers think of camera resolution as a measure of the detail captured in an image. This is generally true, but a more appropriate way to think of it is that resolution relates to how large an image can ultimately be reproduced. The table below shows the relationship between a camera’s resolution and the images the camera can eventually produce. If sensor size was the only thing that defined image quality and detail, it would be child’s play to pick out a camera—with bigger being better—but sadly this simple formula will not serve you well. In addition to sensor size, image detail and quality are affected by such factors as lens quality, file formats, image processing, and photographic essentials such as proper exposure.
Megapixel Decoder Ring
Monitor Resolution
The primary factor in monitor resolution is the actual number of pixels the monitor is able to display. For desktop or laptop LCD displays there is a “native resolution” that represents the actual number of physical light-emitting pixels on the display, and this is the optimal resolution to use for the display. Any other setting will cause degradation in image quality.
The actual resolution is often described not just as the number of pixels across and down, but also with a term that names that resolution. For example, XGA (Extended Graphics Array) is defined as 1024 pixels horizontally by 768 pixels vertically. SXGA (Super Extended Graphics Array) is 1280 by 1024 pixels. There are a variety of such standard resolution settings. In general it’s best to choose a monitor with the highest resolution available so you can see as much of your image as possible at once. However, keep in mind that the higher the resolution, the smaller the screen’s interface elements will appear on your monitor.
The monitor resolution you use determines how much information can be displayed. A high-resolution display of 1920×1200 (left) shows more information than a lower-resolution display of 1024×768 (right).
72 PPI?
One of the most common misconceptions about monitor resolution is that monitors display at 72 ppi and that all Web graphics need to be set to 72 ppi. This simply isn’t the case. Back in the early days of personal computing, Apple had a 13-inch display that did indeed operate at 72 ppi. Most monitors these days display at a range between about 85 ppi and 125 ppi. The exact number depends on the pixel dimension resolution and the physical size of the monitor. Again, this number is a measure of pixel density, so it relates to the overall image quality of the display. The higher the ppi value, the crisper the display and the more capable the monitor is of showing fine detail without as much magnification.
In terms of Web display, the monitor that is used to view the Web page determines the final pixel distribution, meaning you don’t need to make sure that every image you post to the Web is set to 72 ppi.
Printer Resolution
For photographers, the digital image’s defining moment is when ink meets paper. The final print is the culmination of all the work that has gone into the image, from the original concept, the click of the shutter, and the optimization process to the final print. The quality of that final print is partly determined by the printer resolution.
Once again, just to keep things confusing (we mean interesting) there are two numbers that are often labeled “print resolution”—output resolution and print resolution, and this is a major source of confusion. The marketing efforts of printer manufacturers only contribute to this confusion (see the following section, “Marketing Hype”).
Output resolution in the image file is simply a matter of how the pixels are spread out in the image, which in turn determines how large the image will print and to a certain extent the quality you can obtain in the print.
Printer resolution is the measure of how closely the printer places the dots on paper. This is a major factor in the amount of detail the printer can render—and therefore the ultimate quality of the print. Note that the printer’s resolution is determined by the number of ink droplets being placed in a given area, not by the number of pixels in your image. Therefore, there won’t necessarily be a direct correlation between output and printer resolutions, because multiple ink droplets are used to generate the individual pixels in the image.
Each type of printer, and in fact each printer model, is capable of a different resolution.
Marketing Hype
It’s bad enough that the term resolution is defined in a variety of ways, making it potentially a confusing topic. But to us it seems as if the manufacturers of digital photography tools are trying to confuse everyone even further. It doesn’t help that there aren’t definitive definitions for many of the terms being used to describe various products. For example, the term resolution is used to describe the quality a printer is capable of. However, the number by itself is meaningless because so many other factors go into the final image’s quality. Therefore, the only way to use the number is to compare it with the numbers presented for competing printers and to put those numbers in context with other factors, such as the number of inks, the accuracy of dot placement, the dithering patterns, and more. What manufacturers are really trying to do is convince you that their numbers and products are the best, but as we all know the truth can get lost in the hype.
Digital camera manufacturers are quick to boast about the number of megapixels a camera is able to capture. This is an important factor to consider, but other important factors also impact final image quality. Keep in mind that you may not necessarily need the camera with the most megapixels for your particular needs. Also, you can generally push digital images to large output sizes even if you don’t have the highest resolution to begin with. Other factors, such as lens quality and choices, sensor quality, and special features—such as video or a high ISO or frame rate—are also important when you’re deciding which camera is best for you or whether to upgrade from your current camera.
The most marketing hype seems to revolve around photo inkjet printers. There is a constant barrage of claims of how many dots per inch the latest printer can produce. Repeated testing has convinced us that photographic output above 1440 dpi as set in the printer driver produces no benefit in terms of image quality.
By understanding what the various specifications mean and determining which factors are important to you, you’ll be able to see through the hype and make the best purchasing decision.
Bit depth describes the number of bits used to store a value, and the number of possible values grows exponentially with the number of bits.
Bit Depth
A single bit can store two values (ostensibly zero and one, but for our pur- poses it is more useful to think of this as black or white), whereas 2 bits can store four possible values (black, white, and two shades of gray), and so on. Digital image files are stored using either 8 or 16 bits for each of the three color (red, green, blue) channels that define pixel values, and HDR (high dynamic range) images are processed and stored as 32-bit images.
As the bit depth increases, the number of possible tonal values grows exponentially.
8 Bit vs. 16 Bit
The difference between an 8-bit and a 16-bit image file is the number of tonal values that can be recorded. (Anything over 8 bits per channel is generally referred to as high bit.) An 8-bit-per-channel capture contains up to 256 tonal values for each of the three color channels, because each bit can store one of two possible values, and there are 8 bits. That translates into two raised to the power of eight, which results in 256 possible tonal values. A 16-bit image can store up to 65,536 tonal values per channel, or two raised to the power of 16. The actual analog-to-digital conversion that takes place within digital cameras supports 8 bits (256 tonal values per channel), 12 bits (4,096 tonal values per channel), 14 bits (16,384 tonal values per channel), or 16 bits (65,536 tonal values per channel) with most cameras using 12 bits or 14 bits. When working with a single exposure, imaging software only supports 8-bit and 16-bit-per-channel modes; anything over 8 bits per channel will be stored as a 16-bit-per-channel image, even if the image doesn’t actually contain that level of information.
When you start with a high-bit image by capturing the image in the RAW file format, you have more tonal information available when making your adjustments. Even if your adjustments—such as increases in contrast or other changes—cause a loss of certain tonal values, the huge number of available values means you’ll almost certainly end up with many more tonal values per channel than if you started with an 8-bit file. That means that even with relatively large adjustments in a high-bit file, you can still end up with perfectly smooth gradations in the final output.
Working in 16-bit-per-channel mode offers a number of advantages, not the least of which is helping to ensure smooth gradations of tone and color within the image, even with the application of strong adjustments to the image. Because the bit depth is doubled for a 16-bit-per-channel image relative to an 8-bit-per-channel image, this means the actual file size will be double. However, since image quality is our primary concern we feel the advantages of a high-bit workflow far exceed the (relatively low) extra storage costs and other drawbacks, and thus recommend always working in 16-bit-per-channel mode
If you are going to submit a long correction to an article, then at least get it right.
Resolution is not measured in Mp and is not a property of a sensor. It is measured in line pairs per millimetre or line pairs per picture height and it is property of the image cast by the lens.
The number of Mp in the sensor, or PPI considered in conjunction with the sensor size and technology is a proxy for sampling frequency. It sets an upper limit to the amount that can be captured of the resolution delivered by lens.
DPI is a measure of the number of dots in a printed image. A modern printer typically maps each supplied pixel to as many dots as it takes to output 1200 DPI or more.
Electronic shutters also had problems with blooming when strong lights and the sun were in the frame.
Val, whether your camera can use mechanical or electronic shutter is actually depended on sensor readout architecture. Simply put electronic shutters cannot sometimes be used because sensor has to be completely shielded from light during the readout…And you want to have readout architecture under mechanical shutter because you get better performance of your sensor this way…
I went through the most of these steps when I was considering between Nikon Df/610 and Olympus OMD EM1. The output media resolution bottleneck, lens quality and ease of carrying the camera at all times made me choose the Oly.
You know, my D3200 is just great (lots of pixels and all) as long as I have a great lens on it. So, for me (broke at the moment), it’s all about good glass; prints will then take care of themselves, even larger prints, if I have the glass I need.
I picked up a camera about a year ago and quickly discovered that I was not terribly interested in point and shoot and almost put the camera down until I found your blog. Thank you for the time and care you put into explaining everything photography, in a clear straightforward manner.
You are most welcome! Thank you for your feedback!
Nasim, a worthwhile lesson in Megapixel appreciation.
I have owned three DSLR’s in the past 5 years, moving from 12 to 16 and now 24 Mpx.
I found out that the Mpix was calculated by the product of the height x width before the first switch. My main motive for the switch was in order to crop out the sometimes badly composed images I got. Oftentimes you notice that there is actually a ‘picture’ within the full ‘picture’ and the ability to crop that out, and still be left with a high quality image, is a solid gold investment for me as a keen but part-time / fair weather landscape enthusiast.
This was only enhanced when I moved from 16 to 24 Mpix, allowing tighter crops, for the same quality end result.
I can remember Scott Kelby’s book, the Digital Photographer, had a page on resolution which gave a chart showing enlargement sizes, of prints, and the Mpix quality required to achieve them, in high quality. The bar is set surprisingly low. I think it topped out at just 8 Mpix for a 20 x 16″ print. In his words, anything higher is just wasted.
I wouldn’t completely agree with that statement, but the ethos of it is sound enough. I think 16Mpix for a very large print like that is far more than enough, and beyond this, we are into my game – i.e. cropping the original image.
When you think of it, using the image from the new 50Mpix Canons’, and then cropping off the top and bottom of the image, would give you the same effect as maybe five images shot separately and then ‘stitched’.
So I guess for certain things, we can look to these higher resolutions, but otherwise, if you are getting your composition right most of the time, and don’t find you need to crop out more than 5% of the original, you are better served with the 16Mpix camera you already use, and spend the money on better glass, or travel, or accessories etc.
Good article, as usual, very interesting for those who needed reminding of the calculation for Mpix etc. (me for one!).
Thank you for your feedback Ross!
As for the prints, it really depends on what you are looking for and what your acceptable level of detail is. As I have stated in some of the comments above, some people want to see a lot of detail in images, so they print at very large PPI numbers. Others are not interested in looking at extreme detail at close range and have less demands. It all depends on what one wants to see in their prints…
I think 16 MP is plenty for most photographers out there, but if one chooses more, they must have their reasons for doing so :)
Nasim, thank you for an excellent article. I have not found a detailed and “simple” article describing the process of getting our digital files ready for print. For example, I have used Perfect Resize to process some landscape images to print at 24″ x 36″ taken with a D610 and was pleased with the results. However, after reading Betty’s comment above regarding Epson’s native 360 PPI requirement does that mean that if I resize a file for output and select 240 dpi/PPI given the anticipated viewing distance, and use a vendor printing on Epson hardware, that the printer will use its own internal software to increase the file’s pixel density to 360? Is Epson’s algorithm better/worse/no different than say PR or PS’s resizing options? I ask because given the subject matter of the subject article perhaps you can shed some light and guidance regarding the printing process.
Thanks again for your efforts.
Jose
Being in the publishing business, I can add that digital cameras were useless for years after they first got available, because, in addition to being unable to deliver satisfying IQ, they were far from the 300dpi resolution required for quality printing of decent-size images in books—actually before the 12MP sensors, no way one could print a full page photo from a DSLR in a quality magazine or book. That’s why we had to rely for so long on scanning film negatives or slides to print such images as we are used to seeing in, say, National Geo, or any art book. And that is the reason why many professional photographers did not turn to digital photography at that time: they simply could not do their job.
Nowadays those limits are gone and both size and outstanding IQ are available. Even uselessly large images, I hear some say. However, being able to crop and choose a detail in a picture—and most of the time we do crop—is an invaluable asset. I don’t know if 50MB sensors are this necessary, but the 36MB are not too much in the professional world of printing.
Now, for the Internet, screen display and standard high quality prints (10x15cm [4″x6″] up to 25x30cm [10″x12″] or even more), a 12MP-16MP camera is the best possible choice for the ones who know how to frame. The only advantage of bigger resolution sensor is related to cropping, and jamming 40MP in the diminutive sensor of a phone camera is preposterous—sorry, but that had to be said…
Like you, I switched from Nikon F5 to digital when Nikon brought out the D2x – for the same reasons.
However, even then a drum scan of a transparency was still ahead by a good margin.
And even now, I can make a large print from such a scan and would challenge anyone to be able to tell the difference from a similar print from a 12-15 MP digital camera.
Yes, phone camera sensors and their ‘optics’ are preposterous.
But careful, some enthusiasts out there are quite sensitive about this inconvenient truth.
Sure, Betty, some people are sensitive, but the sensible ones can tell the truth from the marketing lies, and I get on fine with sensible people… :-) Apart from that, it is true that the usefulness of a given device depends on what it is used for. For exemple, a terrible video from a dash cam can be the most appropriate thing if it gives us footage that we would have been unable to record with a DSLR for want of time. Better something than nothing.
And true about the drum scan you mentioned—I remember making 100MB+ files out of an Ektachrome 64 slide… Yes, over 100MB and that was some 20 years ago. It kind of dwarfs the 50MB full frame sensor to come, doesn’t it?
Megapixel=MP
You are writing MB which is size of a digital file. Any digital file not just pictures. I fail to see how size of a file relates to it’s print ability ? Surely you do know that file types use different form of compression so a 100MB tiff file can be saved as 20MB PNG file and still print at exaktly same size and same quality.
I hope I am not misunderstanding, but the size of a file (amount of data and bit depth) is very relevant to print quality.
The more the merrier.
100MB for a 35mm scan sounds about right. I have 35 mm drum scans as big as 135-290MB and medium format scans of well over 800MB which when saved with post process layers etc, top out at over 4GB!
Betty you are absolutely correct when it comes to amount of data and bit depth but and this is very important, size of a file depends solely on what file format you have used to save that file. Some formats have no compression what so ever and size of a file is huge, some formats have loosy compresion and file size is smal (JPEG) others have non destructive compression and are bit bigger.What I don’t understand is why Jean is talking about file SIZE when article is about Megapixels (resolution) those two should not be confused.
Agreed – file size and file resolution should not be confused.
Nasim,
I think the relation of pixel pitch size and dynamic range are relevant topics that do worth the discussion.
David, I did not want to open up that discussion, since the article is mostly for beginner and intermediate level photographers and dynamic range can be a bit too heavy to talk about.
While in theory pixel pitch has a direct relationship with dynamic range, it can get quite complex depending on how you look at it. If you down-sample to 8 MP like DxOMark does, sensors with small pixels do amazingly well. Also, DxOMark shows that sensor size does not really matter – MF, FF or crop sensor all seem to produce solid DR. Lastly, sensor technology and pipeline are key in DR performance: Canon has been falling behind in those two areas when compared to competition…
Nice article.
I do think though that the issue of diffraction should probably be more prominent in the discussion. As the pixel count goes up, and the sensor receptors get smaller, the effective use of smaller f-stops disappears. This is a major issue for landscape photographers where depth of field is very important. With some of the higher MP counts out now, like the d800 and even 16mp crop sensors, diffraction is apparent even at f8 and fairly significant by f11.
The print issue is another that is a bit misleading (not just here but generally). Technically, one would never want to resample to size for a print, but that just isn’t practical–resizing is always destructive. Printing at a native resolution as you suggest will certainly yield the best print, however, I am not sure that anyone would actually see the difference except maybe with a loop if the print is made properly. I have been making large prints since the mid-90’s and with a good resizing algorithm–using the right one in PS–print sizes equivalent to dividing 100 into the pixel dimension will turn out fabulous–that would be a 60 inch print from a 6000 pixel wide sensor (You do need to resample them up to the optimal dpi for the printer you are using–at least 200dpi for a Lambda and preferably 360 for an Epson Large format printer) I made a couple of 50 inch prints from the 12+mp original 5D for my assistant and even flowing strands of hair were perfectly rendered.
Diffraction is important. But using higher MP sensors and better lenses produces still better results beyond the diffraction limit (higher MTF values are reached before diffraction takes its toll) . This is clearly explained in this Zeiss document: . So stopping down to f16 on a D700 and D810 still benefits the D810.
Nice document, diffraction is truly fascinating phenomenon. It is not by chance that this year Nobel prize in Chemistry was awarded for practically beating it in optical microscopes.
I think there are two different things working here. Resolution will be better overall, however, if diffraction is more significant on one camera than the other, then you probably aren’t better off. My own tests, practical, seem to lean towards the lower MP camera doing better than the higher MP camera at those f-stops–a visual thing ;))
Interesting. The Zeiss measurements compare a 12MP and 24MP camera, with benefits for the higher MP camera. But it is highly lens dependent.
John, it also depends on how you are viewing and printing those images. At pixel level, the higher resolution image will show diffraction more, but if you down-sample it, it will not be any different…
John, true, diffraction does become a problem as the size of pixel is reduced and resolution goes up, but like HF stated below, there is still an advantage on the higher megapixel sensor, especially when it is normalized / down-sampled to similar size as lower resolution camera.
As for printing, I guess it really depends on what you consider acceptable. While up-sampling can yield pretty good results, that process cannot compete with real pixel-level data from a high resolution image. There are people out there that stitch gigapixel panoramas and print with insane detail at 720 PPI, way more than your eye can discern, even at very close viewing distances. The amount of details in those prints is incredible and regular up-sampled images could never compete with those. So it is truly a matter of personal preference and what you are printing. For portraiture and other day to day work, 12 MP should be plenty. For ultra high resolution landscape work, the more pixels in an image, the better…
“I guess it really depends on what you consider acceptable.”
That’s sort of rude, if I may say. Anyway, I think I know what a good print looks like.
We can get so over focused with these “tech” concerns that we actually lose perspective. I was clear in my comment that theoretically it is best to print with native resolutions, however, as you said, at some point the eye doesn’t actually see the detail. Careful up-sampled images will compare favorably to prints at a native resolution, believe me, I have more than a little experience in this area.
John, please do not get offended – my intent was not to be rude, but to show that it all depends on how acceptable one considers details in a print. I do not doubt your experience and I am sure you know a lot about printing. However, please do take a look at prints made at 720 ppi to understand what I am talking about – Ming Thein has been selling 720 ppi prints for a while now and you can see the immense detail in his photos right here. If the goal is to print that detailed, then upsampling simply won’t do the job, because you cannot dig through that much detail in a 8-16 MP image.
“…to show that it all depends on how acceptable one considers details in a print….”
And that is my same concern and what I suggest does work. But I never mention any MP parameters nor did I suggest one can make something appear that doesn’t exist.
I think we have to be careful that we don’t get so enamored with tech issues that we lose focus on the real importance of our photography, to share our view of the world. Tech matters only when those tech concerns actually limit what we are doing with our work and how we use it.
Photography as an art and exceptional examples of it by today’s standard rely on state of the art in “tech” more today than ever before. That’s the nature of photography, which after all depends on the extremely advanced tech of even the most simplistic camera/lens/sensor or film. It’s been that way since the arts inception and today the standards to rise above mediocrity are only higher: larger prints, greater dynamic range, lower noise and greater bit depth. This is why many photographers are attracted to the medium as it continues to evolve and rewrite the standards. Great photographers today have mastered the fundamentals of the exposure triangle, composition, color, contrast, etc. The next level for them is beyond the limits of todays gear. To sentimentalize the nostalgia of yesterdays “good enough” gear is to ignore the possibilities of tomorrow art. If stagnation is your idea of excellence then I suggest you pick up a brush and excel beyond the masters.
Sorry, but I do Ctr-C Ctrl-V
lazy-flyer.livejournal.com/198159.html
Many thanks Nasim :)
Спасибо Владимир!
Thank you Nasim for the article. Just a small detail, when comparing the resolution of D700 and D800, you compare the increase in linear resolution and pixel count difference (73% vs 300%). I think it would be better to write either 173% vs 300% (difference) or 73% vs 200% (increase).
Jan, thank you for your suggestion. You are absolutely correct and I went ahead and changed the numbers per your recommendation.
Hi Nasim I also think you have your models mixed up the D7100 is a 16 mpx
The d7200 is 24mpx
This has been the best article I have ever read! I can now understand some of the technical aspects. Before everything was just a mumble, jumble mess of figures I couldn’t understand. Thanks!
With regard to print size difference at 12MP and 36MP …
Though what you say about it is right, it’s not wrong either to claim that the print will be three times bigger at the same DPI/PPI setting … It’s just that some people talk about area size, while others talk about length of the sides.
For anyone with a basic background in mathematics, a print is a two-dimensional affair, thus the measure is area size rather than side length. (Think about real estate: a square site is usually referred to as being four times bigger, if the sides are twice as long …)
Many people will think about the side length, but keep in mind that many people interested in cameras and active on forums are often more on the technical side of the spectrum.
Florian, that’s why I stated both numbers in area and in linear width, so that one can understand it better. I just think many confuse MP numbers with length, which happens quite often in discussions…
Hi Nasim, just to chime in on the sensor size/pixel size discussion.
Noise is actually more determined by sensor size than pixel size. Imagine a constant aperture and pointing at the same object. The projected image has identical surface brightness on the sensor. A larger sensor captures more light than a smaller one, conversely the actual gain is lesser (ISO is a false number) and therefore it appears than the larger sensor has less noise.
Pixel size only matters when things are taken more to the extremes. e.g. a 4mp phone sensor vs a 40mp phone sensor. Assuming constant pixel gap spacing, the 40mp phone wastes a large amount of the surface area to the gaps, which isn’t actively collecting light.
Another thing which pixel size affects is full well depth. effectively how much charge per pixel can hold. that directly affects the bit depth of the output which affects the dynamic range.
cheers!
I might be wrong, but I think that sensor size over pixel size idea only holds if you deal with bright enough images, while when your signal level is low (image is not bright enough) pixel size actually matters more…
I think it’s a little of both.
Imagine the same aperture and the same field of view for FX and DX. Since the surface brightness of the projected image is the same, the FX sensor collects 1.5x more light than the DX sensor, assuming the same shutter.
To create the same output, the actual gain is pushed higher on the DX sensor. But since the ISO follows a standard, not the actual gain on the sensor, the ISO listed is the same. This is why FX handles low light better than DX at the same ISO.
Pixel size I would think is more of a sweet spot thing. More pixel = more read noise etc = poorer image quality. Assuming same sized sensor, larger pixels tends to win the low light race.
Yes, at low light read noise is big and then the more pixels in a sensor (or smaller pixels) the noisier the image.
Just curious. would any one of your guys be interested in a 4mp compact camera if it performs as well in low light as a APS-C camera? For travel and leisure purposes of course
I have a point-and-shot that nicely fits into my packet and still comes with a nice f2 lens on it (Panasonic Lumix LX3). I take it with me whenever I do not want to carry around big bag and still take some photos. I always use it in its automatic iA mode, shoot JPEGs and never post-process these photos. I would certainly buy it with half MP inside (but exact same, relatively new package and not a decade old bulky digital) if I was to save money this way, but this is not how the market works unfortunately…
what if it came with interchangeable lens, Zeiss build quality, 7x crop factor (200mm = 1400mm) and HD video?
I already explained what for and how I use it, so what do you think?
probably nope lol
But if you can strip my Panasonic of MPs and give me a $$ difference, I will probably add another Ai prime to my Nikon system.
You are correct. This is why the Sony A7s with its 12 megapixels is so much better at low light than the Sony A7r. Problem is, people will always think more is better with megapixels. But in reality there is a sweet spot depending on what you’re trying to accomplish with your camera. And people will have to learn to use the right tools for the right job.
It will be fun shooting landscapes with that Canon 5Ds at f5.6 and focus stacking to gain depth and resolution with out dipping into the diminishing returns of diffraction at higher apertures. It could be fun experiment for sure.
Whilst you are right that it is about the right tool for the job, it doesn’t tell the whole story. The A7s beats out the A7r for low light in part because it was designed that way, it loses out at low ISO shooting as a consequence – tradeoff in sensor design. Is it possible to create a high res sensor that performs equally well (once downscaled to 12mp) as the A7s? I’m not sure, but from a business point of view, it doesn’t make sense to sacrifice low ISO on a high res sensor which appeals to the landscape crowd where maximum FPS isn’t as important. The Canon 5Ds(r) looks to be even more specialised than the A7r with stronger CFA for better low ISO color separation as a design principle.
What about foveon sensor? (just to mess around :p!)it is said to have twice the clarity of Bayer design. Anyone has experienced?
If you really want to know, I invite you to read my recent discussion with Spy Black on that topic (comments in my profile). I will only say here that Foveon is capable of producing full resolution color images (unlike sensors with bayer filters), however Foveon senors overall performance is far from Sony sensors for reasons Spy Black mentioned…
Mhm I just read. I still don’t get the thing entirely… Ok, full color spectrum, non interpolated images, no moiré neither low pass filters… less DR for sure too. But in term of equivalent I was wondering til what size you can upsize a Merrill file. Camera store review did it and found it amazingly close to d800. Ok print size show that so yes let’s say 15.3 foveon worth 30.6 but even without low pass filter still don’t understand why ^^!
3 layer stack design of Foveon sensor not only allows capturing full RGB information into each pixel but also eliminates chromatic aliasing because colors are separated into each layer as three full resolution images so you do not need AA filter with Foveon (Foveon has only layer of microlenses helping you to avoid artifacts). As for comparisons I do not see a point in calculating equivalents here, just enjoy advantages of both.
True and agreed, however I was just discussing about the topic, bringing something different to the talk
Ive recently read bunch of articles how great are these big numbers megapixels cameras. (even if nobody even touch them yet) and I get the feeling that some of them are just to encourage people to buy some new fancy stuff. But lets be honest. 99,9% of photographers use their photos to publish over the internet or to print them small or medium size (not like half the wall size). Now my screen has the resolution like 1920×1080 so … Now how different will be looking on my screen photo from 50mpix or 24 mpix or 12mpix camera? If the photo is properly done, the answer is THE SAME because all of them will be displayed in resolution 1920×1080 not a pixel more. If you print, its not hard to get 300DPI. From 12mpix its 36x24cm and from 24mpix its 51×34 cm. Its HUGE , more than enough for wedding photographers.
All am saying is that its really hard to show difference to anyone.Not to mention difference in pixel size on a sensor makes huge difference in low light. Just check old full frame camera and new fancy apsc. So its very important to know all pros and cons. Thats why its very nice article. Am not denying the progress in technology, I know that in a few years we all gonna have 100mpix cameras. but I feel like we should really use our brains and decide what is good for us. For example the biggest chart here: if you stack 4x times 12mpix you get 1 from 50mpix. Its pure math but it changes really nothing at least for me. If i switch from 50 mpix to 12 mpix , its not like my photos will be 4 times smaller. They will just have worse resolution. I think such things should have an explanation. To sum up its a great article with many good points and I cant wait to read next one.
When will the 300 ppi myth fade? Many quality labs do not even print that high. 250 ppi is more standard IMO and you can get away with even less depending on the medium (canvas).
Not necessarily so.
300ppi is a good number for most inkjets but it all depends on what standard you are working to.
I use a RIP (ImagePrint) to drive my printer (EpsonPro 4900) and this prints natively at 360ppi.
If you give it a file that doesn’t have sufficient pixels, it will interpolate until it does.
The results are generally acknowledged to be the best in the business (inkjet that is)
And if you print on paper made from elephant dung you can get away with almost anything.
Do you live on this website?
Ah, it may seem so to you, but no, I pop up sporadically when I have time on my hands and a topic interests me.
….And especially when someone on the internet is wrong…
You are right, I can probably get away with 50 ppi printing on elephant dung paper, but I was trying to stick to the real world. Printing on canvas is very popular and does not require as high of a resolution.
Thank you for your input. You sarcasm is very much appreciated.
Always happy to oblige.
By the way, elephant dung paper actually exists – and is not unlike canvas – well no, it is a bit rougher and doesn’t smell as nice. I am not sure whether its available both coated and uncoated though.
Also, I would question whether canvas requires less resolution.
If that were the case why do we use increased sharpening for printing on matte art papers and canvas?
It seems to me that increased resolution might be a plus and in any event is unlikely to hurt.
If you’ve got it why not use it?
Different mediums show different levels of detail: glossy vs matte vs canvas are all different IMO. I think its important to note that in case someone wants to print larger but does not have the resolution, you can get more acceptable product on a large canvas than you would on a large glossy print.
I agree completely with that.
It is not really a myth – a lot of people print at 300 ppi still and believe it or not, but there are a few people out there that now print at much higher number, closer to 720 ppi, which is insane amount of detail.
I dont mean that its a myth that printers have specs capable of printing that high, I mean that it doesnt seem to make a difference for real world printing. I have yet to see a real world print test that shows any difference between a 250 ppi print and a 300 ppi print. I would love to see an article from you that debunks that notion and shows that 300 ppi is really necessary.
Absolutely. I have just printed a 2.2 Mp image at A3 size. It is a crop from an image made with my very first digital camera nearly two decades ago, a 3.5Mp Powershot. It looks no different, quality-wise, than any of my 16.7 Mp images printed at the same size at close to the widely recommended 300 PPI. I strongly suspect that most of the people repeating the advice they have read (about DPI and print quality) have never made a large print in their lives.
I have both iPhone and iPad and have used cameras on both about 5 times just can’t hold then steady enough to take decent pictures. They are great for view picturestaken on other devices. I don’t think it’s a fault of Apple. It more of the form factor size and weight.
Hi Nasim!
It seems to me that you couldn’t completely wrap your head around the concept of percent yet.
Ján Halaša already mentioned the mistakes you made when comparing the INCREASE of horizontal pixels between the D700 and the D800 which is 73% vs. 200% (and not 173% vs. 300% as you say). You said that you corrected it which you actually didn’t.
A little further down in your article you basically make the same mistake again when you write “…the Nikon D7100 has a sensor size of 23.5 x 15.6mm, while the sensor on the Nikon D750 measures 35.9 x 24.0mm – 152% larger in linear width…”. But actually it is 53% LARGER in width. Yes, it is 153% THE SIZE in width but its only 53% LARGER.
The following sentence should therefore read: “…the physical size of each pixel on the D750 sensor is 53% / 1.53x larger in comparison.”
When you talk about differences:
If A is 100% larger than B it means that A has twice the size of B.
If A is 0% larger than B it means that A and B have the same size.
When you talk about absolutes:
If A has 200% of the size of B it means that A has twice the size of B.
If A has 100% of the size of B it means that A and B have the same size.
I hope you don’t think I’m a math nazi now, but I maintain a photography website myself (www.focrates.com) and I am always greatful when people correct me on the countless mistakes I make.
Thanks for your great efforts in providing this website and best regards,
Ben
Ben, thanks for letting me know. Earlier today I just went ahead and changed the numbers in front of percentages and added a “1” in front without even re-reading the sentences. You are right, I messed it up, even the part that was originally just fine (52%).
Hope it looks better now! :)
Since when to more megapixels give a larger field of view? Maybe you would care to rethink the use of the illustration showing megapixels superimposed on the mountain.
Jim, you are right – there is no change in FoV, I simply could not make a better illustration when I worked on the article. I am currently redoing that to show the same image at different MP. Hope it will look better. Thank you for your feedback!
Jim, just posted the updated version – hope it represents the reality better :)
Just a side comment – I love your pika pics. I lived for 30 years in the area and never got such good photos. Of course, I never had anything longer than 200mm, either.
Now back to the MP discussions.
Thank you Shane, I appreciate your feedback :) Back when I captured those pikas, you could get down the trail on trail ridge road in RMNP and capture them at very close distances – I have a few samples taken at 200mm as well. But last time I had been there, there was a sign that you could no longer walk down there…
That graphic is a little misleading. It seems to be implying the higher MP you have the more image in the frame, meaning the less a of cropping factor. To my knowledge the only thing that effects the crop ratio is the size of the mirror not MP count. www.laesieworks.com/digic…_sizes.gif
Billy, it is a bit misleading, but I could not wrap my head around how to best present it. There is no difference in FoV, just size differences in print. Perhaps a better way to present is to present the same photo in each print – I am currently redoing that and hopefully it will look better.
Billy, please see the updated article – hopefully the illustration shows it better now.
Excellent article. Truly useful and so detailed. It is a joy to read your analysis and insights of photography and techniques and I can share it with pleasure with my fellow photographer friends. Fantastic work, Nasim!
Nasim, thanks for the revised illustration and article. Good work.
3times is already 3times:
Dear Nasim,
i think you made a mistake, if you’re posting 3times of Resolution would not be really 3times. You are right if you claim an increase of 73% or Factor 1.4 in higher resolution inline one of the edges. But, if you calculate the whole image size you’re getting the same 3times of resolution. In example, the proper maximum of printing size for the D3 is 14.2″ x 9.4″, which is 133.5 square inch. For the D800 it is 24.5″ x 16.4″, which is 401.8 square inch. In this case, the print is 3times bigger, simple. Not 3times on each edge but over the whole square indeed. Your example suggest, that this wouldn’t be the fact, but it is.
best Regards, flat D
Very nice and thorough article. Thank you!
I would just like to point out, that in the example with the DX camera Nikon D7100 and the FX D750, the FX-pixels are a factor 2,32 bigger than DX-pixels. (35,64 square µm, versus 15,37 square µm). So the FX-pixel will be able to collect 232 photons every time the DX-pixel collects 100 photons. The same approximate factor applies when comparing the area of the whole FX-sensor with the area of the DX-sensor. So there is actually quite a big difference between FX- and DX-sensors.
Gr8 article. Depending on one’s grasp and ability to proliferate the info and the links , it’s one huge ocean of knowledge . I am limited on both counts ;-p Keep up the good work my friend , NASIM MANSUROV .
Hi Nasim,
Love the honest reviews & website, I’m a semi-pro wildlife photographer that travels to Africa 3/4 times a year.
Just a quick question re. downsampling.
Have recently purchased the D810 (to use in conjunction with my D4s) on my newly purchased 400/2.8E, and wanted an opinion regarding whether it’s best to use DX crop mode or shoot in FX and crop later. You mentioned that the ISO quality will improve once downsampling/resizing an image to 12/15MP, I’m gathering it WON’T be the same if I use DX crop mode as a means of downsampling, as some early test shots seem to bare this out.
Needing to shoot at f/2.8 & f/4 in the dawn/dusk hours, and not wanting to use my 1.4tc where I’ll lose 1 stop, my intention was to use DX crop mode (on the D810) when required if I need to get closer during this time.
It’s that old conundrum us wildlife shooters face in trying to find the best solution that will get us reach with good Hi ISO quality, my guess is to play it by ear and assess each situation and flick between the D4s & 810.
Your thoughts?
BTW, I shoot in M mode in conjunction with Auto ISO.
Fuck You
Wonderful articles you write. Thank you.
Question : I see Nikon D40 is having about 6MP on a APSC sensor.
If one want only to stick to smaller prints and web based images, going by pixel size ( of camera sensor)
should D40 be a better option ( better image quality) than the new cameras like D3300 which has 24MP on ASPC sensor
Again am comparing 6MP usage on the APSC sensor here?
In the article you refer to printing at 300 PPI. Don’t you mean 300 DPI? I came to this article for a more specific definition of camera resolution not the total number of pixels available on the sensor. For a person with normal vision acuity what would be a reasonable PPI?
I stopped the final sentence in mid-thought.
…what would be a reasonable PPI for a photo held at arms length?
I have recently tried taking a camera phone picture of a 17th century etching. I expected that all the lines of the etching would appear on the phone screen when the image was expanded and also when sent to email. But not so. Why Surely any line that the eye can see to draw should appear in the image. Its possible that the fine lines were created using magnification to create finer lines but surely the lines should still appear. What does seem to appear is a technical optical illusion. The screen cannot produce an exact image of the fine lines but creates something different. How can I get an exact reproduction or is this impossible. Thank you for any answer.
Hi,
I just read your articles about the whole pixel issues. I also went through you little guide in which I went through my Lightroom catalog to finde out in which iso range I made the moste pictures. I used to work until this year with my Nikon D80. I own already two FX lenses 50mm and a 70-200mm. So I was planing to buy myself either the Nikon d750 with some accessories or I would buy the Nikon d700 and get an additional lens because I know glas matters the most. Since I am new in the full frame are it would make sense to me to get the d700 learn to handle an FX body and than in two year getting myself a better FX body. Would this make sense to you if I am totally new in the FX world?
I am photographing microminerals with a standard Nikon Coolpix 995 equipped with an additional microscope objective in front of the lens. I generally shoot 1X pictures but occasionally want to achieve higher magnification to resolve detail. I have camera and lens combinations that reach 10X (image size on sensor), but, increased magnification above 2X doesn’t seem to improve the details. What is causing the limited resolution ? Is it Optics, sensor, lighting ?
You lost me with this paragraph. In fact the second print IS exactly 3x larger than the first. It is only 73% wider. The first print is 133 Sq inches and the second is 402 sq inches. You are only defining large by width but the print has gained height and area.
“Basically, if you could print a detailed 14.2″ x 9.4″ print at 300 PPI with the D700, upgrading to the D800 would potentially result in a 24.5″ x 16.4″ print at the same 300 PPI. Hence, moving up from 12 MP to 36 MP would translate to 73% and not 3x larger prints. Again, it is easy to confuse total area with horizontal width, so it is important to understand the difference here.”
Remove the obscenity in the November comment ?
My needs are very basic. I build a website to promote my fledgling career as a singer in pubs, clubs, and restaurants.
I expect my visitors to be viewing my images always on a computer’s display screen.
On the site I have 1) a large image (say 10 inches by 10 inches) when I display the home page, 2) a smaller image (say 3 inches by 3 inches) for each sub-page and 3) a large image again when I display a musical slideshow.
I also make 4) posters which I send to friends; they might 4) display it on their computers or 5) print it to make a flier to distribute physically.
I gather all my images from Pixabay and constrain them to be at least 1280 by 720 pixels. How ‘good’ is this for the five purposes I have named above?
I have, perhaps, slightly unrelated question:
I own now older but trusted Canon 1D Mk3 and wanted to know if when changing the size of the photos inside the camera (from largest “L” to “Medium 2″ or Medium M1” or “Small”), does the camera use the entire sensor or it reduces the number of pixels used during exposure before it re-sizes them?
So, basically how do the images change quality-wise as their respective sized do?
Somewhere I read that smaller images receive some sort of interpolation processing and therefore are more sharp — that’s aside from pure laws of physics when smaller-sized photos seem sharper.
There are many posts about advantages of higher resolution, but nowhere have I found an answer to my question.
I enjoy reading your comprehensive and well-thought out articles, so perhaps you could shed some light.
Thank you,
Alex
Thank you, Nasim. That was a really helpful article, cogently expressed, articulate, and it explained clearly exactly what I wanted to know – as well as things I didn’t know I wanted to know.
Terrific.