Kodak to produce 8mm film camera

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Diffraction is not a worry. S8 film is not 4k, it isn't even HD, it resolves somewhere around SD quality. Back in the day we had S8 cameras that would stop down to f/45.
 
Diffraction limitations get worse as the recording medium size is reduced, you can get away with f45 on an 8x10 film, but it would be nothing but mush on a 35mm film size given the same viewing size. Since we are speaking of standardized viewing sizes of say 1280x720 pixels, the tiny sensor is going to show more softening from the larger circle of confusion because the larger circle occupies more sensor (or film in this case). Blowing the original up to the viewing size shows the loss of details. No one knows this better than pinhole photographers where the images themselves are formed from diffraction and interference effects. 8x10 or larger film used in pinhole looks fairly good, 35mm not as good (when viewed at normal sizes of say 8x10).

http://www.bobatkins.com/photography/technical/diffraction.html

So slamming ND in front and using an appropriate iris opening, you can maximize the image. Just because the lens goes to f45 doesn't mean you should be using it.

http://www.bobatkins.com/photography/technical/diffraction.html

Norman Koren had a much more math heavy explanation here for those that really want to know http://www.normankoren.com/Tutorials/MTF6.html

For 8mm it looks like we are looking at f4 or f5.6 as maximum sharpness which is fairly shallow depth of field (assuming a decent lens which could be quite an assumption for these cameras).
 
Super 8 has a frame size about the same as a 1/3" sensor, and resolves about standard def resolution. The lower the res of the sensor, the less the impact of diffraction. You can easily get HD resolution on a 1/4" sensor, although the diffraction limit is very tight. An s8 sensor is much bigger than 1/4", and its resolvable detail is far lower. F/45 might produce absolute mush on a 1/4" Hd sensor, but may still result in usable footage on S8, especially given the sharpness limitations of typical S8 lenses.

Now, granted, I haven't shot s8 at f/45 on purpose, and certainly not in the last 35-40 years, but I don't generally recall there being much concern about diffraction on S8. It would be pretty tough to get an S8 camera to f/45 anyway; you'd generally be shooting 50 ISO when in daylight.

Diffraction is a huge issue in something like a 1!4" HD or 1/3" 4k camera because it happens very quickly and under quite wide f-stops (like f/2.8 to f/4). The low res of S8 and its comparatively larger sensor mean that the effects of diffraction aren't likely to actually impair shooting in most scenarios.
 
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