A reader sent a nice message today which included the following:
I am always amazed by the detail of your photographs, the sharpness (I sometimes wish you’d elaborate a bit more on your settings of the shot ).
Thanks for the nice comment about detail and sharpness. Let me give a little overview of some of what I do. (Of course, to really see this you would have to look at a print. :-)
Almost all of the photopraphs were made with either an 8 megapixel Canon 350D/XT or more recently with a 12 megapixel Canon 5D.
I use high end Canon lenses – 17-40mm f/4 L, 24-105mm f/4 IS L, 70-200mm f/4 L, 50mm f/1.4.
I tend to shoot at smaller apertures unless the depth of field requirements of the shot (or limited light and moving subjects) require larger apertures. For sharpness across the frame, I generally shoot at f/8 on the crop sensor 350D and at f/11 or f/16 of the full frame 5D.
In most cases I shoot from a tripod and use a remote release and mirror lockup.
I post-process photographs and appropriately “work” the images using methods comparable to those used by traditional film photographers (dodging, burning, contrast selections, etc.) and some that are available in Photoshop (localized levels, saturation, color balance, and others).
I apply two stages of sharpening to the full size images. First I apply “smart sharpening” to produce the greatest micro detail, while being careful to avoid unnatural sharpening artifacts. Then I apply some unsharp masking to provide “local contrast enhancement.”
After downsizing the images for posting here, I do one more subtle unsharp mask operation to slightly increase detail in the smaller .jpg versions posted on the web.
Whew!
And that’s only a general summary. Individual images require different processing and different techniques. For example, it would not have been appropriate to do a lot of sharpening in my recently-posted photograph of evening rain in Yosemite Valley. On the other hand, in order to produce the best image it is sometimes necessary to use even more extensive post-processing techniques, such as in recent photos of early morning on the floor of Yosemite Valley, where the scene had an extremely wide dynamic range.
I’m usually happy to explain more about a particular image if you are interested, so just ask! :-)
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(Note: This article was originally posted in 2007 and I should probably update the test using newer gear – though the point of the test and the post remains.)
Last month I wrote about a set of tests (“Full Frame Lens Test“) that I conducted with my lenses and my Canon 5D body. My object was simply to better understand how the camera/lens combinations would behave so that I could make better decisions about appropriate lenses and apertures while making photographs.
One discovery was that, compared to using a crop sensor DSLR, I can get excellent results when I shoot at smaller apertures with good lenses on the full frame body. I tended to avoid apertures smaller than about f/8 on the crop sensor camera, but there seems to be little or no real liability in using f/11 or even f/16 on full frame.
To illustrate I put together the following composite image. (The image appears in reduced form on this page. Click the link to see the full size version.)
A sequence of text photographs illustrating diffraction blur at several apertures on a full frame camera
The example includes five versions of a small section from near the center of a photograph taken with the Canon EOS 5D using the EF 24-105mm L IS lens at a 50mm focal length. The camera was on a tripod, MLU and a remote release were used, and the AF was turned off. The images are 100% crops – in other words, actual pixel size is displayed in these tiny excepts from the much larger original images. (You would virtually never view a print at this magnification. These are equivalent to tiny sections from a print that might be about 5 feet wide!) The images have been slightly sharpened in post-processing, but are otherwise unaltered.
I shot at apertures of f/4, f/5.6, f/8, f/11, and f/16. In terms of the sharpness of this portion of the image, I am quite certain that all five examples are plenty sharp for making prints. That said, there are some differences. To my eye:
The f/4 and, to some extent, the f/5.6 versions are slightly but noticeably softer at this magnification.
The f/8 and f/11 versions seem to me to have approximately equal sharpness. Some parts of the f/8 image seem slightly sharper, but other parts of the f/11 image seem sharper. In the end they are pretty darn equivalent, though I’d maybe give the f/11 a very slight edge overall.
The f/16 image may be slightly less sharp than the f/8 and f/11 versions, but the difference would not be noticeable in a print, even a rather large one. In any case, f/16 appears sharper than either f/4 or f/5.6.
After doing this test I no longer hesitate to shoot at f/11 or f/16. Not only does this give me the possibility of getting greater depth of field when I need it, but it also means that I can compensate for corner softness on some lenses (e.g. the 17-40mm) by using a smaller aperture without fear of losing center sharpness.
(Addition: 4/23/07 – Other Canon L lenses seem to give similar results, including my 17-40mm f/4 L and my 70-200mm f/4 L.)
Added 2/23/08:
In response to a question in a photo forum I put together a sample image showing corner sharpness from the same original images used in the example above. (The earlier example shows 100% crops from near the center of the frame.)
(image temporarily unavailable)
Technical info: Shot using a Canon 5D with the Canon EF 24-105mm f/4 L IS lens at a 50mm focal length. In aperture priority mode, the aperture was changed manually between shots. Initial focus was with AF, which was then switched off before shooting the series. Camera was on a tripod and MLU and remote release were used. Shots were converted from RAW with ACR and no additional post-processing applied. Print made at this resolution would be approximately five feet wide. The crop is from the far lower left corner of the frame.
In addition to noting the softer image in the corner at f/4, also note that the image is a bit darker due to the expected increase in corner light fall-off (“vignetting”) at the largest aperture. Sharpest version in this series shot with a FF body seems to be at f/11 as in the center crop example above. But note that f/8, f/11, and f/16 are not very different in overall sharpness – and in the end any of these apertures would produce a very sharp print.
In response to another forum discussion, I have added another example, this time using the Canon EF 50mm f/1.4 lens and showing performance at f/5.6, f/8, f/11, and f/16. In other respects the test is the same as described already in this post. This image is seen to the right and below.
(image temporarily unavailable)
Conclusions: Based on this set of images and other taken with different lenses under similar conditions, I have come to some conclusions that work for me with my Canon lenses and full-frame Canon 5D body.
In general the sharpest whole aperture seems to be around f/11.
It is very difficult to distinguish any resolution differences at f/8 or f/16 – there are subtle differences when viewing the test images at 100% magnification on my monitor but these are essentially invisible in prints.
f/5.6 or f/22 will tend to be a bit less sharp, though perhaps not for the same reasons. At f/5.6 I begin to notice a bit more of the diminished sharpness as a lens is opened up – more on some lenses than on others. At f/22 the effects of diffraction become just a bit more noticeable. However, if the shot demands it I do not hesitate (much) to use either of these apertures as the very slight decrease in sharpness is quite tiny if visible at all in a print and both provide some other advantages in certain situations. (I’ll even use the largest f/4 aperture on the test lens when isolating the subject is important or when low light demands it – and the results will typically be just fine.)
At larger apertures the performance becomes more tied to the particular lens so it is more difficult to make any generalizations beyond the fact that vignetting increases and sharpness will be less optimal.
The smaller apertures decrease any corner light fall-off (“vignetting”) or softness, generally to a point where both are insignificant.
With all of this in mind, unless I have a reason to select some other aperture I typically use f/11 as my general starting point when shooting with my full-frame DSLR body.
G Dan Mitchell is a California photographer whose subjects include the Pacific coast, redwood forests, central California oak/grasslands, the Sierra Nevada, California deserts, urban landscapes, night photography, and more. Blog | About | Flickr | Twitter | Facebook | Google+ | 500px.com | LinkedIn | Email
From time to time I shoot indoor theatrical or musical performances where the use of flash would be inappropriate… and probably get me ejected from the theatre! From what I understand, many people like to photograph these subjects with primes (for their wider apertures) or with wide aperture zooms. I have successfully shot such subjects with the former, but I don’t own the latter.
Newer DSLRs that have image stabilization and can produce good low-noise images at higher ISO values let us push the limits of natural light photography in these situations.
This example was shot with my EF 24-105mm f/4 IS zoom on a tripod and with image stabilization. (I leave the ballhead somewhat loose and sometimes use the tripod as a monopod.) I can often shoot in the 1/25 to 1/60 of a second shutter speed range and get good results as long as my subjects aren’t moving too fast.
Jim followed up on my reply to his initial question by supplying a couple of sample photos that he was not totally happy with. I won’t reproduce them here since they aren’t my photos, among other reasons, but I will post a few comments and observations.
The two photos were both taken in Yosemite, this summer I think. I took a more careful look at a photo that I think I recognize as being taken along the Tuolumne River in Tuolumne Meadows, with Mt. Gibb in the distance. I have several observations about this photo:
The exposure seems pretty good. Judging from the jpg I saw, it may be slightly underexposed – the histogram stops a bit before the right edge and detail is missing in the shadows of the trees on the right side. (This detail might still be recoverable in the RAW file.)
It looks like the photo was made at a f/22… and this likely is a problem as far as sharpness is concerned. The best aperture for optimum sharpness on crop sensor cameras is generally right around f/8, plus/minus a stop or so. While closing down (e.g. – f/22) would seem to provide greater depth of field, it also emphasizes diffraction effects that decrease the maximum sharpness of the lens. Imagine that you were perfectly focused on an object at f/8; you would likely be obtaining the sharpest possible image of that object. Now decrease the aperture to f/22; this object in the focus plane is now less sharp than it was at f/8. In Jim’s photo, most of the scene is a pretty good distance away… and out of focus due to diffraction. There is little to gain by increasing depth of field, and I suspect that the small aperture is responsible for the fuzzy focus.
In terms of effective framing of the scene, this might be more effective with a tighter crop. There is not enough to hold my interest on the right and left margins or in the foreground, so cropping some of these areas out of the frame might produce a more effective image I think. (It might be possible to go for a squarer format and do most of the cropping from the sides.)
There is a strong blue cast on parts of the water’s surface, probably picked up from the sky. I would adjust this by selecting this area (with a feathered edge) and reducing overall saturation and especially saturation in the blues.
Other parts of the image might be improved by a bit more saturation – perhaps about a 10 or 12 setting in PS.
I would perhaps make a feathered selection of the distant ridge and by levels or curves adjustments give it a bit more contrast.
The other photo is of an impressive scene that almost all Yosemite visitors have gawked at – including me. It was shot along the road descending into the valley from the north, looking east into the valley.
The difficulty with this shot is mostly the lighting. This is a very difficult place to photograph unless the light is just right, typically very early or late in the day during the summer. It looks to me like Jim was there during the middle of the day when the light is almost directly overhead and is quite harsh – tough conditions!
I didn’t take a close look at the technical aspects of this image, though it does appear to be fairly well exposed. It may be a bit overexposed, judging from the histogram of the blue channel which picks up the intense blue of the sky – but again there is a good chance that this could be handled in the RAW conversion.
