Quote Originally Posted by brucemuir View Post
... I was taught in school that it did exist but it wasn't a huge deal and my experiences bear me out on 6x6
When I was learning my hasselblad I routinely would stop way down to f/32 when trying to shoot architecture with the 150 Sonnar.

I noticed a 50mm Nikkor I had only went to f/16 so I figured if it was available it couldn't be too awfully detrimental.

I did know that lenses had a sweet spot but it never stopped me from using smaller apertures.

Now I shoot people mostly so I'm usually at almost wide open most of the time.
Lens manufacturers design aperture limits while taking diffraction into account. That's why a 35mm lens is limited to larger aperture settings than a large-format lens. The influence of diffraction also depends on print enlargement. If one routinely makes 8x10 prints of medium-format negatives, diffraction will never be an issue. But, a medium-format lens, such as the 150mm Sonnar, has twice the resolution at f/8, compared to f/32. Given a substantial enlargement, that will be clearly visible.

Having said all of that, one should not hesitate to use all available aperture settings unless critical resolution cannot be sacrificed. Aperture settings are a photographic tool to optimize image composition, and should be used as such. Diffraction concerns are secondary. As you explained, apertures are chosen depending on subject matter not to minimize diffraction.

There is nothing worse than a sharp picture of a fuzzy concept!
Ansel Adams