Category Archives: Commentary

When Inspiration Takes a Vacation

May 2, 2011 G Dan Mitchell 10 Comments

It happens to (almost) everyone. The pendulum sometimes swings towards enthusiasm, inspiration, and creative work that almost seems to flow all by itself. But pendulums swing both directions, and one of the prices we pay for doing creative work is having to cope with the inevitable dry periods when enthusiasm, inspiration, and creativity are nowhere to be found, periods when you can find yourself questioning your talent and abilities. (I think that one characteristic of “mature” artists is that they understand this cycle and are less likely to be undone by it – both because they are familiar with its existence and because they have learned ways to deal with it.)

I don’t claim to be the definitive expert on this issue, but I have some experience with it in both photography and music. There is much more to be said about this than I have space for here, but I thought I’d share a reply I wrote in a forum where a poster posed the following: Continue reading When Inspiration Takes a Vacation →

Commentary, Equipment

Why Your 21MP File “Looks Softer” Than Your 12MP File at 100% Magnification

May 1, 2011 G Dan Mitchell 5 Comments

(Note: 21MP cameras were state-of-the-art when I wrote this. While that is no longer the case, the explanation of the concept still applies to comparisons between more recent higher MP cameras cameras with differing sensor resolutions. And, years later, camera reviewers are still making the mistake that I address here.)

A frequent photography discussion forum meme is that “this old camera with fewer photosites produces sharper images than this newer camera with more photosites. In fact, I have carefully inspected 100% crops from both and the evidence is clear!”

Not so fast.

Let’s imagine that the comparison is being made between the full-frame 12MP Canon 5D and the full-frame 21MP Canon 5D2, both of which I own and use. If you put the same lens on both cameras, set the lens to the same aperture, and point both cameras at the same subject, the lens will project exactly the same image onto the sensors of both. Let’s say that you do this under controlled conditions, and you decide to compare the two captures to see if the 21MP camera is really sharper than the 12MP camera.

You want to compare closely, so you display both images as “100% magnification crops” – portions of the image that show each individual pixel from the original photograph as an individual pixel on your computer monitor. You display the two images side by side and, squinting closely and looking back and forth between the two, you notice that the 21MP original is certainly no sharper than the 12MP original and that the 21MP image actually looks a bit less sharp! You decide that a) higher MP cameras are less sharp than lower MP cameras (you have the evidence!), and/or b) the camera companies are pulling a fast one on us.

You are actually wrong. Dead wrong.

When gazing too long and too intently at a computer screen, it is easy to forget that the real world is not always represented accurately on the screen. In this case, the error is a result of viewing on a computer screen rather than making more realistic comparisons, for example between two prints of equal size. With the screen image comparison, you might overlook a fact that explains why the sharper (or at least equally sharp) camera appears to be less sharp. A look at the above illustration will help.

The image includes two copies of a full-frame photograph. Think of the one on the left as representing the photograph made on a 12 MP camera (like the 5D) and the one on the right as representing a 21MP camera (like the 5D2). The original 5D image would be 2912 pixels wide, while the original 5D2 image would be 3744 pixels wide. The full-color area of each image represents the part of the original image that would fill the screen of a 1280 x 1024 monitor when the originals are viewed at 100% magnification.

The critical point illustrated here is that the 1280 x 1024 “slice” of the 21MP image shows a considerably smaller portion of the overall image, and in order to fill the same size screen it will have to be magnified more than the image from the 12MP camera. If the two images are equally sharp to begin with, the one that has to be magnified more to fill the screen will lose more of its original resolution because you are looking more closely at a smaller portion of the image.

In the end, if you were to make two prints of the same dimension from the two original full images, the higher MP original would look at least as sharp as the lower MP original, and if you use good lenses and good technique (and print large enough that it makes a difference) the higher MP version has the potential to resolve more detail.

Some related points

A few related notions about sharpness and megapixel resolution also come up from time to time, and those who believe in them can be quite stubborn about their misunderstandings. Here are a couple:

Claim: When you move to a higher MP sensor your photos will be more susceptible to motion blur.False. This is not the case at all. If you make otherwise identical photographs with a low MP full frame (or other format) digital camera and a higher MP camera using the same format, prints of the same size from both sources will have exactly the same amount of motion blur. (Technically, the higher MP camera will provide a more accurate image of the blur, but that doesn’t change how much blur there is.) In both cases the blur covers the same percentage of frame width. And, if you are tempted to check 100% magnification crops to prove me wrong, don’t forget what we saw above about looking more closely at a smaller area with the higher MP example. (The good news for the higher MP sensor is that when there is less motion blur it has the potential to produce an even higher resolution image of the subject.)
Claim: Because the diffraction-limited aperture is larger when you work with higher resolution sensors, you’ll have more blur at smaller apertures with the higher MP system.False. You’ll have exactly the same amount of diffraction at every aperture. Diffraction is an optical phenomenon that is not affected by the sensor. Once again, if you make prints at some size from otherwise identical frames from a higher and lower resolution system, at every aperture diffraction will affect both the same way. And, again, while the higher MP system is never worse, if you use a very good lens and open up a bit you may get an even sharper image from the higher MP system.

In every case, either the two systems perform the same or the higher MP system is better. There is no situation in which the lower MP system will produce a sharper print at a given size, and there are some in which the higher MP system will make a sharper print… or allow one to make a larger print with the same resolution.

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Commentary, News, Photographs: Death Valley, Site News

G Dan Mitchell Photographs at Stovepipe Wells

April 30, 2011 G Dan Mitchell 8 Comments

G Dan Mitchell Photographs, Stovepipe Wells Lodge

Since several people have asked, I thought I would share an update on installation of my photographs at the historic Stovepipe Wells Lodge in Death Valley National Park. Late last year Ortega Family Enterprises (who also sell some of my photographs at Muir Woods National Monument) contacted me. They were about to take over the management of the facility from the previous concessionaire and were interested in selling some of my Death Valley photographs in the gift shop at Stovepipe Wells.

It turns out that they were also planning some significant upgrades to the lodging facilities at Stovepipe and they asked if I could provide a large number of 16″ x 24″ prints for the guest rooms. To make a long story short, they selected a half dozen of my Death Valley photographs and I went to work making nearly 170 prints of the six photographs, which were then shipped off to their framer for final preparation.

I finally got a chance to see the results when I visited Death Vally in early April. I stopped by and found out that they had begun the process of hanging the prints in guest rooms, and with the help of an employee I was able to get in long enough to snap a shot of one of the rooms. (Hanging in this room are “Transverse Dunes, Death Valley“ and “Crossing Tracks, Racetrack Playa.”) It was also good to see some work being done to upgrade and update the lodge!

It is gratifying to have my photographs installed here for several reasons. Several of the photographs were made virtually within walking distance of Stovepipe Wells, where I often camp when I visit the Valley. I also know that among the many people who visit Stovepipe will be a good number of my fellow photographers – and knowing that they will see my prints here is both a bit intimidating and a quite exciting! Finally, before Ortega took over the facility I often stopped to look at some of the photographs and paintings that had been there previously. (I was glad to see that one wonderful black and white photograph was still hanging in the hotel office.) With that in mind, it seems like there is a good chance that these photographs of mine may be hanging in this historic facility for some time to come!

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Commentary, Equipment, Technique, Tests

“My Photos Are Soft!”

April 28, 2011 G Dan Mitchell 4 Comments

So, you have a camera or lens that you think is not as sharp as it should be. If you are already expert at these things, what follows is not for you – you already know how to analyze the problem, you can anticipate possible causes, and you know some of the pitfalls of looking at the issue in unrealistic ways. But if you aren’t certain about how to deal with the issue, perhaps the following might help… so feel free to read on.

Perhaps you just got a new lens or a new camera and you don’t think it is performing as you expected. Or perhaps you have long suspected a problem with your equipment. On the other hand, maybe some gear that you have used with confidence for a while seems to not work as well as you recall it working in the past. It can be tempting to blame the equipment – and in some cases you may be correct – but it is a very good idea to first try to analyze and understand the problem and look for other possible causes… and solutions.

It is critical that you try to control the variables that might give rise to the issue, and then to try to a) determine if the problem is real, and b) figure out specifically what might be the cause. The range of possible causes is larger than you might imagine: problems with the camera’s autofocus (AF) system, an out of adjustment or “weak” lens, less than optimal choice of lens settings, issues with camera stability, insufficient care with the use of AF, using the wrong AF settings, aperture choices, shutter speed choices, subject motion, and more. While a real equipment problem is a possibility, it is probably at least as likely that the problem lies elsewhere. Fortunately there are ways to wade through this minefield and develop some rational understanding of what is going on.

What follows is a sort of ad hoc description of how I might approach this. It is not meant to be the only way to deal with such issues, it leaves out some possibilities, and the sequence could be changed around in some ways. Continue reading “My Photos Are Soft!” →

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