There have been some interesting discussions about the pros and cons of various sensor sizes and how they impact angle of view, lens focal length and the depth-of-field that results. For example, some photographers bemoan the fact that it is difficult to achieve a shallow depth of field at a particular equivalent-field-of-view with a CX sensor using 1 Nikon lenses, while others find it useful to be able to get deeper depth-of-field at more open aperture settings such as f/1.8 and f/2. Some D800 shooters are concerned about diffraction setting in above f/8 when trying to achieve deep depth-of-field with a high pixel density 36mp FX sensor, as are many photographers who use high pixel density sensor DX bodies.
Whether you’re an amateur or professional shooter the choice of which camera brand and format to buy can be daunting. Often after you’ve shot with it for a while another round of soul-searching can happen as you better understand the strengths and limitations of your gear, and consider where your photography and/or videography is going to take you. I suppose we all go on our own ‘gear journey’…this is mine.
Because the glass elements in a camera lens are round, lenses project a circular image onto a camera’s sensor plane. This projected image circle must be large enough to cover the rectangular sensor, like so:
It seems like the debate of DX vs FX for wildlife and sports photography is a never ending one. DX shooters argue that they get more reach, stating that DX is like a “built-in 1.5x teleconverter”, or that DX setups are lighter due to smaller lenses and less expensive, or that DX chops off the corners of lenses, thus reducing vignetting and other optical issues. On the opposite side of the fence, FX shooters argue that they get better image quality at pixel level, better viewfinder, less diffraction issues, better AF performance in low-light, etc. Seems like we have two camps, each defending their own side for various reasons. Having spent a number of years shooting both DX and FX starting from the first generation Nikon FX cameras and every single DX camera manufactured by Nikon to date, and having talked to a number of other photographers that shoot for a living, I came to a conclusion that there are some myths surrounding the DX format that need to be debunked. In this article, I will provide my personal insight to this topic and explain why I believe that FX is always better for photographing sports and wildlife. This article evolved as a result of recent discussions of the subject with some of our readers.
1) The Myth of the DX Built-in 1.5x Teleconverter
A lot of people seem to be very confused about the effect of a crop sensor on the focal length of a lens. Stating that a crop sensor increases the focal length of the lens or acts as a teleconverter is completely wrong, since focal length is an optical attribute of a lens and has nothing to do with the camera. I talked about this in detail in my “Equivalent Focal Length” article that I published a while ago. Simply put, a DX sensor can never change the optical parameters of a lens, so if you are shooting with a 300mm lens, it stays as a 300mm lens no matter what camera you mount it on. The confusion of “equivalent focal length” comes from manufacturers that initially wanted to make people understand that the field of view on a cropped sensor camera is tighter than 35mm, because the image corners get chopped off. The word “equivalent” is only relative to 35mm film. So you cannot say that your 300mm lens becomes a 450mm lens on a DX body. It does not and never will. All you are doing, is you are taking an image from a 300mm lens, cropping it in the center area and magnifying that center with increased resolution.
2) DX Pixel Size and Resolution
The only reason why some people thought that DX provided longer reach, was because DX sensors historically had similar resolution as FX. For example, both Nikon D300 (DX) and D700 (FX) have about the same resolution – 12 MP. So despite having sensors of completely different sizes, the two cameras produce images of similar size / resolution. Ultimately, this means that the D300 can resolve more detail from the center of the lens (which is typically the sharpest on any lens) and thus magnifies the subject more, which led people to believe that DX was better than FX to get closer to subjects. One aspect that was rarely talked about, however, was the fact that the D300 has a lot more noise than the D700 due to smaller pixel size. So despite having this magnification advantage, photographers had to constantly deal with cleaning up apparent noise even at relatively low ISO levels. I personally had to constantly down-sample images and clean them up via noise-reduction software to get rid of the artifacts visible at anything above ISO 800 (and noise was visible even at base ISO!). So at the end of the day, taking a DX image and down-sampling it aggressively, versus simply cropping an FX image produced somewhat similar results, with a slight advantage on DX that resulted in more detailed shots, thanks to the down-sampling process.
In this article, I will show feature differences between the new full-frame Nikon D600 (FX) and the older cropped sensor Nikon D7000 (DX). I have received a number of requests from our readers asking me to provide this comparison, since many photographers are considering to move to the Nikon D600 from their D7000 cameras. Please keep in mind that this Nikon D600 vs D7000 comparison is purely based on specifications. A detailed comparison with image samples and ISO comparisons is provided in the Nikon D600 Review.
Although I called this article Why DX has no future, I believe it applies to all cropped sensor DSLR cameras, not just Nikon. Earlier in 2012, I wrote an article called “The Future of Digital Cameras“, where I shared my thoughts on what I think will happen with DSLR, Mirrorless and other camera technologies within the next few years. One of the main points of the article, was my opinion on DSLRs and why I think they are here to stay for a long time. I did not clarify what I meant by DSLRs, because the DSLR technology defines how the camera works, not what type of sensor or features it has.
As I am sure you already know, DSLRs today come in different sensor sizes. There are expensive, pro-level DSLRs with full-frame sensors equivalent to 35mm film in size, as well as cheaper DSLRs with much smaller sensors (about twice smaller in size than 35mm, generally referred to as “APS-C”). Historically, DSLR manufacturers have been producing APS-C cropped-sensor cameras for three main reasons: lower cost, smaller size and lower weight. The smaller size of the sensor meant that the camera’s internal components such as the reflex mirror could also be made smaller and the entire frame of the lens did not have to be used, making cropped-sensor DSLRs and lenses lighter, more affordable and a little more compact in comparison (see my DX vs FX article).
The End of the Small Compact and the Rise of the Mirrorless
With personal computing making its way to phones and tablets, instantly reaching millions of people, the message has been clear – people want smaller and more capable devices. This change in consumer behavior is very obvious. If just a couple of years ago the general population was carrying compact digital cameras to capture their everyday moments, now most people just resort to smartphones with built-in cameras. We live in a very connected world today and people are willing to give up a little on quality, as long as they are able to instantly share a picture or video with friends and relatives. They do not want to carry multiple devices – convenience has become hugely important. That’s what has been shattering the compact camera market for sometime now and as I have previously pointed out, I believe the small sensor compact market will pretty much disappear within the next few years.
Some of the most frequently asked questions from our readers are around DX and FX format sensors. What is DX and FX? What are their differences? Which one is better and why? If you have similar questions and want to get a clear understanding about these formats and their differences, along with seeing actual image samples from both, this article is for you.
Before diving into sensor formats, it is first important to understand what a sensor is and what it does in a Digital SLR camera. It is easier to understand how sensors work by comparing them with the human eye. The lens in front of the camera essentially functions as the cornea of your eyes, gathering ambient light and passing it to the iris. The iris then expands or shrinks, controlling the amount of light that enters the retina, which functions almost exactly like a camera sensor. The retina is light-sensitive, meaning it can adjust its sensitivity based on the available light. If there is too much light, it decreases its sensitivity, while automatically increasing the sensitivity in a dim environment, so that you could see in both extremely bright and extremely dark conditions. Remember what happens when you come out of a dark place to a very bright, sunny environment and vice-versa? Either your eyes will hurt and everything will seem too bright, or you will have a hard time seeing at all – due to sensitivity of the eyes that have not yet adjusted for the new environment. The sensitivity of your eyes is just like the sensitivity of the sensor, also known as “ISO” in photography. But sensitivity comes at a price – high sensitivity levels ultimately decrease image quality, similar to when you have a hard time seeing in a very dark environment. This degradation of image quality is first visible as “grain” or “noise” in the pictures, followed by loss of detail, sharpness and color in extreme levels of sensitivity. When I say “extreme”, I mean extreme to the digital camera, not human eye. Even with all of the latest advancements in sensor technology, cameras are not even close to seeing the range of light the human eye can see in various environments.