Lens that works well at f/22?

[chriznatch]

Can anyone recommend a lens that works well at small apertures? I've heard that many lenses have issues at f/22 and smaller. Although I use my camera in a variety of settings, I have in mind the typical travel shot where you put someone in front of a distant building or landmark and try to get both in focus. The lens that I currently use (the Sony 18-200 on an A100) does not seem to do particularly well in that situation; I've actually had better luck using a point and shoot. Any recommendations would be much appreciated. Thanks

[Dr. Harout]

Try to use a prime wide angle lens such as 20/2 and close the aperture to f/11 and imho you'll get what you want. The hyperfocal distance for wide angles gets quite big for apertures greater than 8 (in number, of course)

[David Kilpatrick]

On APS-C, you can work one stop wider, so f/16 is going to give you as much depth of field as f/22 does on full frame (or did) for the same angle. I have done tests in the studio, where small apertures are needed for product photos, and find that f/13 is the last point at which the image does not begin to soften slightly. I suggest trying f/11 if the depth will be adequate.

If you take an f/22 shot, try changing the JPEG sharpness to +3 before you shoot (or do a similar extra sharpening in raw). It will overcome the diffraction sharpness loss visually.

David

[01af]

Can anyone recommend a lens that works well at small apertures?

Nobody can. Because the loss of sharpness at very small apertures has nothing to do with the properties or qualities of the lens; it's due to the laws of physics (see keyword 'diffraction').

The aperture at which diffraction losses become evident upon close inspection of the image depends on several factors, among them the image format being the most significant. So on APS-C format it's around f/11. On 35-mm format it's around f/16. On 4.5 × 6 cm medium format it's around f/22. On 6 × 7 cm medium format it's around f/32. And so on. When doubling the linear size of the format then the aperture limit goes up by two f-stops.

When stopping down further than that then depth-of-field will still increase but maximum sharpness will suffer. There is no lens in the world that can circumvent this rule. If you really need more depth-of-field then don't hesitate to stop down further, as more depth-of-field can visually outweigh the loss of maximum sharpness so the image will appear sharper to the eye overall. But if the impact of the image does not depend on extreme depth-of-field then avoid stopping down too far.

When shooting digitally and in need of extreme depth-of-field then consider taking several shots at different focus settings and adding them to a composite which appears sharp from front to back. Adding several frames taken with different settings does not only work for exposure ('DRI' or 'HDR') but also for focus. There is even software that helps stacking those frames but you can also do it manually. Of course, this trick will work for static subjects only.

-- Olaf

[chriznatch]

Thanks everyone for the responses. I'll try a wide-angle lens with the aperture at f/11 or f/13 and see if that improves my travel shots.