Lens Calibration Explained

Lens Calibration Explained

If you are wondering about how to calibrate lenses, this article has detailed explanations and different methods of AF fine tuning. Due to the nature of the phase detect autofocus system that is present on all SLR cameras, both cameras and lenses must be properly calibrated by manufacturers in order to yield sharp images. Various factors such as manufacturer defects, sample variation, insufficient quality assurance testing/tuning and improper shipping and handling can all negatively impact autofocus precision. A lot of photographers get frustrated after spending thousands of dollars on camera equipment and not being able to get anything in focus. After receiving a number of emails from our readers requesting help on how to calibrate lenses, I decided to write this tutorial on ways to properly fine tune focus on cameras and lenses. Lens calibration is a complex topic for many, so my goal is to make this guide as simple as possible, so that you could manage the process by yourself, while fully understanding the entire process. In addition, I strongly recommend to follow these tips every time you purchase a camera or a lens in order to identify and address any potential focusing issues. But I have to warn you – this article is NOT for beginners. If you just got your first DSLR, you might get very quickly frustrated with the calibration process.

Lens Calibration Explained

1) Why Calibrate?

Why is there a need to calibrate lenses? With the release of new, high-resolution cameras like Nikon D800, it seems like calibration is becoming an important and hot topic. Why is that? As I have explained in a number of my photography articles and reviews, while the increase of megapixels in our cameras has a number of benefits (see benefits of high resolution cameras), it can also expose potential focus problems. A slight focus issue might not be as noticeable on a 10-12 MP sensor, but will be much more noticeable on a 25+ MP sensor (assuming both sensors are of the same size). Especially when viewed at 100%, which is what we, photographers unfortunately like to do too much. Hence, the need for a properly calibrated camera setup today is bigger than ever.

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Nikon D600 vs D7000

Nikon D600 vs D7000

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.

Nikon D600 vs D7000

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Nikon D600 vs Canon 6D

D600 vs 6D

With Canon having recently announced its take on budget DSLRs, the Canon 6D, the most obvious rival just happens to be the brand new Nikon D600. We’ve already seen how the latter stacks up, at least on-paper, with such great cameras as D700 and D800, but neither of those cameras were direct rivals. Priced at the same relatively low price for a full-frame sensor camera, $2099 body only, Canon 6D is as direct a rival as it can get. Lets see how it measures up against its Nikon counterpart spec-wise. Please keep in mind that this Nikon D600 vs Canon 6D comparison is purely based on specifications. A detailed comparison with image samples and ISO comparisons will be provided in the upcoming Canon 6D Review.

UPDATE: there has been a misleading set of specifications spread throughout the internet, indicating that the top shutter speed of Canon 6D is 1/8000th of a second. It’s incorrect – according to official Canon specifications, the top shutter speed of their newly announced “budget” full-frame camera is 1/4000th of a second.

D600 vs 6D

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Nikon D600 Limitations

Nikon D600

Since the Nikon D600 DSLR has been released this morning, I have been receiving a number of emails and comments about it from our readers. Looks like there is some confusion about the capabilities and limitations of the camera. A number of online resources are talking about the D600 and thanks to some famous bloggers, people now think that the D600 has serious problems. I am not here to defend the camera that I have not touched yet, but I would like to clarify these issues so that there is no misunderstanding or confusion.

Nikon D600

1) Sharp Images

After I posted the Nikon D600 Sample Images, some of our readers started questioning the quality of the camera, blaming softer images (particularly from the owl shot) on the camera. First of all (and I am sure most photographers already know this), the softness of images has little to do with the camera. Even the cheapest entry-level DSLRs like the D3200 are capable of producing very sharp images. Take a look at my article on making sharp images and you will know exactly what I mean.

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Nikon D600 vs D800

Nikon D600 vs D800

Here is another quick specifications comparison between the new Nikon D600 and the D800 that was announced earlier in 2012. I am sure many photographers will be interested in seeing feature differences between the resolution king, the D800, and the $900 cheaper D600. Looks like both cameras are quickly becoming popular among many amateur and professional photographers, so what feature advantages does the former offer over the latter? Let’s take a look in this Nikon D600 vs D800 comparison. Please keep in mind that this comparison is purely based on specifications. A detailed comparison with image samples and ISO comparisons is provided in the Nikon D600 Review right here.

Nikon D600 vs D800

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Nikon D600 vs D700

Nikon D600 vs D700

Now that the Nikon D600 is officially out, I am sure many photographers will be interested in seeing feature differences between the old and discontinued Nikon D700 and the new D600. Please keep in mind that this Nikon D600 vs D700 comparison is purely based on specifications. Note: a detailed comparison with image samples and ISO comparisons is provided in the D600 Review.

Nikon D600 vs D700

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Interview with Norman Koren of Imatest

Norman Koren

A couple of weeks ago I had an opportunity to visit Norman Koren, founder of Imatest, LLC. I have been fascinated by his software for a while now and after evaluating the software, decided to purchase it to use in our lens reviews. When I found out that his company is right here in Boulder, Colorado (where I lived for over 5 years), I gave him a call and asked if I could come over and interview him. Despite his busy and hectic schedule, he was able to accommodate me for an hour during his lunch time. Below is the text version of the interview.

Nasim: Thank you for giving us the opportunity to visit your office and learn more about you and your company. Let’s get started with your background, your company and how it all started.

Norman: You are most welcome Nasim. I grew up in Rochester, NY, about a mile from the George Eastman House, which I visited frequently. Both the technical and artistic exhibits made a deep impression on me—it was there that I first saw the beautiful prints of Ansel Adams and Edward Weston. I had a long career in magnetic recording technology, where my job involved simulating the performance of read, write, signal processing and detection in disk and tape drives. It started back in 1967 at Honeywell in Boston. I then worked for a number of companies including, curiously enough, Kodak in San Diego. Kodak at the time— we are talking 1985— believed that very small tape drives would be used in digital cameras. Well, it didn’t turn out to be a winning technology, but I had an interesting 12 years there. At the same time, I’ve always been a passionate photographer.

Norman Koren

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Nikon DSLR Firmware Recommendations

Nikon D4 Menu - Firmware Update

When Nikon releases a new generation DSLR camera, it seems to often make little changes to the camera firmware. We typically see slight tweaks here and there, but every once in a while (especially when a new piece of technology makes it into the camera) we see some new interesting and useful features getting added into the camera firmware. In this article, I would like to point out current firmware issues that I believe Nikon needs to address, along with some recommendations (wishlist) on what Nikon should do in their future cameras. Or, perhaps Nikon might consider to implement some of the below firmware fixes/recommendations on current DSLRs – I am sure many of the Nikon owners would get excited about some of these requests.

Nikon DSLR Firmware Recommendations

1) Add DNG Support

As a Nikon shooter, you already know how painful it can be to constantly keep updating post-processing software, image codecs and photo viewing programs every time Nikon releases a new camera. Upgrading a camera should be easy and we as consumers should not have to go through this process every time. DNG has already become a universal format and companies like Hasselblad, Leica, Pentax and Samsung have already adopted it. Why not do the same? I am not asking Nikon to abandon its NEF file format. Just give us a choice to pick either NEF or DNG please!

2) Allow AF Fine Tune Calibration of Each Focus Point

Thanks to the recent Nikon D800 Asymmetric Focus fiasco, we now know that each autofocus point is calibrated at the factory during the QA process. We also know that Nikon keeps the ability to tune these AF focus points to their own calibration software. Why not add this capability to every advanced Nikon DSLR where AF fine tune is already provided? Sure, this seems like a headache to implement and could result in a some improperly calibrated cameras out there (due to user error). But for those of us who know what they are doing when it comes to lens and camera calibration, why not give this capability? Nikon would save a lot of money on not having to re-calibrate so many cameras. Adding this feature, of course, would not be an excuse for improperly calibrating cameras, but it would certainly make the AF Fine Tune feature way more useful.

3) Allow AF Fine Tune Calibration for Different Focal Lengths

Those of us that have attempted to calibrate zoom lenses know that one AF Fine Tune value is often not good enough for the whole zoom range. The AF Fine Tune feature would be a lot more useful if we had the ability to use different AF Fine Tune settings depending on the focal length of the lens.

4) Live View at 100% Pixel Level Should be Standard

Nikon’s implementation of Live View on the Nikon D90 was terrible, due to its interpolated output. Since then, Nikon has made many new cameras that had a 100% pixel view, which was very useful in obtaining precise focus on subjects. With the D800, Nikon brought an interpolated live view back (which is one of my biggest complaints on the D800). Nikon should fix this as soon as possible on the D800 and make 100% pixel level live view a standard on all future cameras.

5) Fix Custom Settings Banks

The Custom Settings Banks implementation on Nikon DSLRs is bad and completely impractical. I personally do not bother using them on any of my cameras, because I do not have the time to either switch them in multiple places (Shooting Bank and Custom Settings Bank), or constantly review the settings to make sure that they have not changed. First of all, memory banks should apply to all camera menu items. Second, these settings need to be “lockable”, meaning if anything gets changed, the setting should not get overwritten unless I want it to.

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The Internet’s Influence On Photography – Part II

Steel_City_Blues

Continued from Part I…

5) Out With The Old And In With The… Old!

I find it amusing to observe that long after a technology has been declared dead, it will magically reappear after nostalgic longing causes some to reintroduce it in some form. When I first got back into photography in 2007, I came across a fellow Pittsburgher who had concocted an interesting homemade device consisting of a heavy duty cardboard tube attached to an old, beat up Kodak Duaflex TLR (twin lens reflex) camera, which was quite popular in the 50s and 60s. He attached it to one of Canon’s top DSLR and lens combos. The resulting images were grainy, heavily vignetted, filled with a variety of textures produced by the old scratched lenses, and sported a rough black border. Of course, my first thought was, “So… you bought a high end Canon DSLR and some of the best lenses in order to take pictures while focusing through a 50 year old camera bought at a yard sale for $12?” Just when we thought all those yard sale Kodak TLRs were headed for the scrap heap, thousands of photographers brought them back to life by putting them in front of some of the best DSLRs and lenses of the world. All this to take retro looking photos, which they describe as “edgy.”

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The Internet’s Influence On Photography – Part I

BigBuy

The digital camera revolution, in conjunction with the explosive growth of the internet has had profound changes on photography. Some changes have been dramatic, while others have been more subtle. In times of revolutionary technological changes, it is important to adjust your perspective to the new realities and contemplate just how far we have come. I will put the second part of this article online shortly.

1) Printing & Pioneers – A Little Perspective

If you asked to see someone’s family photos years ago, they would often reach for their wallet or purse, and proudly show you 2X3 photos stored in plastic coverings. Today when you ask the same question, people will almost always reach for their smartphones, and either pull up pictures stored on their mini SD cards or quickly navigate to a website such as flickr. Low cost digital picture frames have also become quite popular, enabling people with little in the way of technical know-how to store hundreds or thousands of photos on an LCD in an attractive picture frame, which cycle through every few seconds.

Kodak

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