Sharpness of lenses for 8mm movie cameras

[Lupton Pittman]

I am looking at footage that I had filmed this year on a Bolex B8. I was filming variously with a 6.5mm f/1.9 Wollensak and a 5.5mm f/1.8 Switar . The Wollensak is fixed focus. The Switar has a focus ring. But, no matter how I focused the Switar, it didn't seem to affect the sharpness of the image too much (maybe I am remembering wrong exactly what I set the focus to each shot). What seemed to affect sharpness more was aperture. I think the Switar took amazing sharp images at like f/2.8, f/4, f/5.6, but was much less sharper at the extreme apertures like f/1.8 and f/22. The Wollensak - which is fixed focus - took overall very good images, but also (like the Switar) created sharper images when set to the "middle aperture range" (maybe like between f/4 and f/8?). So, do you think, that somehow, the focus ring is not really so important on these wide angle 8mm camera lenses for shooting street scenes and landscapes (which is what I mostly have been shooting)? Is sharpness more dependent on which aperture is being used?

If that is the case, then, for very sunny scenes where my light meter is telling me to use f/22 or f/16, do you think I should be using a Neutral Density filter (so that I can open up my lens to say, f/11 or f/8) to get the sharpest image?

[Paul Adsett]

I would certainly recommend using an ND filter for very bright scenes. The problem with f/16 and above on 8mm is that the aperture is so small that it produces diffraction and softening of the image.

[Lupton Pittman]

Thanks for the response. Yes, I am thinking I will start using an ND filter. The bad thing about 8mm is film/processing/transfer costs so much, you will end up spending like $95-$100 total (including postage, etc.) to shoot/process/transfer a roll of film. So, it's like every batch of mistakes you make, you will need to spend another $100 to try to correct your mistakes with a new roll of film and then have to hope that the finished product is actually an improvement from the last time.

I bought a Pentax Q camera and D-Mount to Q-Mount adapter as a test bed for my D-Mount lenses so that I don't have to spend so much money testing them on a real 8mm movie camera, but so far the results have not been the greatest with my wide angle D-Mount lenses (Regular 12.5mm and Telephoto 36mm work better). Some people online say to add some shims in addition to the adapter (some people have focus issues with the adapter alone), but that has not helped me much yet. I am still just starting to experiment with the Pentax Q as a test bed, so maybe my experience will get better.

[Shane C. Collins]

It's why I skip the process of having my reversal films scanned. I save a ton of money just doing things the way it was done in the old days. Shoot, process, and watch on a projector.
when I shoot Ektachrome 100D (7294) Super 8 I always use a ND filter on bright or sunny days. I try to keep the aperture below F 11. Super 8 looks better at the lower f stop settings. As you pointed out the middle aperture settings produce the best images.

[Lupton Pittman]

Yeah, I would skip the scanning step, but I have been shooting on Kodak Vision 3 ASA 50D film for my 8mm camera (I shoot Regular 8mm). That's negative film, so I need to get it scanned.

Thanks for letting me know that you use an ND filter and try to keep the aperture below F/11. That's good to hear some confirmation about my observations/suspicions. I think I will be trying to do the same (use ND filter, try to use the middle range of apertures) with my next roll of film.