Why don't any pro lenses offer smaller than f/32?

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So many times I wish that I could stop down to f/64 or so to get a creative effect with exposure time or D.O.F. For some reason we don't get this choice. I can set all manner of shutter speeds and ISO's but not ever a small aperture. I know that diffraction will be seen but for some subjects the diffraction will be less of a problem than the D.O.F. from the larger aperture. We can set very wide apertures that will give unsharp results but not small ones. Even if the extra small ones were available like Hi-1 and Hi-2 with the ISO settings - like an added boost I would be happy. The results can be quite wonderful.

Would anyone else like to see Nikon give us a couple of lenses with this option?
 

Growltiger

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Diffraction is usually pretty bad at f/22, let alone f/32, and beyond that few people would find the blurry pictures acceptable. No one wants to sell a lens that gives poor results.

You don't say what sort of photos you are taking. Have you used focus stacking. Infinite depth of field and you can use an optimal aperture such as f/11.
 
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If you could buy a lens that stops down to f/64 for 35mm I doubt you would find the results acceptable if sharpness is a criteria.

If you accept figures for CoC and estimates for the limiting aperture for a sharp print for an 8"x10" size then this aperture is f/22 for 35mm film and f/16 for APS sensor.
Have a read http://www.bobatkins.com/photography/technical/diffraction.html
 
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Nikon Micro lenses will show an effective aperture of F64 close up.
 
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Thanks. Yes I know diffraction is an issue but some photos in AP last year were made using a homemade lens with an F90 aperture. Homemade because this aperture was not available for 35mm cameras. The photos showed bees on a flower close up with everything to the horizon in focus. It was a 'bees eye view' I think they called it. I suppose the demand to put such a small aperture in a lens is not worth the R&D but I would still like to try it.
 
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I recently bought the older Nikon 85mm tilt/shift lens and was surprised to see that it goes down to f/45. I haven't really tried much at that aperture.

The newer 85mm one only goes to f/32.

Barry
 
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I can't remmber exactly how the fomulas go but f64 wold have to be a really small hole to shoot through, wouldn't it? On a 35mm Crop camera?
 
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I can't remmber exactly how the fomulas go but f64 wold have to be a really small hole to shoot through, wouldn't it? On a 35mm Crop camera?

Right, and that is of course exactly why we don't see f/64 now.

Ansel Adams promoted f/64 for his landscapes (in the 1930s), but he used an 8x10 inch view camera, with film diagonal nearly 13 inches, or around 325 mm would compute to be called a "normal lens" for him.

Diffraction is not determined by f-number, but instead by smaller aperture diameter.

f/stop = focal length / effective aperture diameter.

So to Ansel, f/64 was about a 325mm/f64 = 5 mm aperture diameter.

28 mm would a "normal lens" for DX today. Less than 1/10 as long, because of the small sensor.
So the same 5 mm aperture would only be 28/5 = f/5.6

So Ansel's f/64 compared to f/5.6 on DX, diffraction wise. (not speaking here of exposure-wise)

f/64 on 28mm would be a diameter of only 28/64 = 0.4mm diameter. Nearing pin hole status. Good luck with that.

The 105mm macro lens may reduce to f/64 exposure wise, but diffraction-wise, it is the same aperture diameter that does f/32 at infinity focus. What changes is that for macro closeups, the focal length increases (extended away from sensor), no longer 105mm.
 

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