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I've tried a bunch of C mount lenses on the Q. I use the two piece C to Q mount adapters for each of my C mount lenses. That allow me to adjust the adapter so that the aperture dial is facing up for each lens. One thing I have found with these lenses is the focal range is off. Infinity focus doesn't match up with the infinity mark on the lens. Infinity is focused at a shorter range.
I ended up buying some brass shims from McMaster Carr to allow me to dial in each lens. I bought 0.01" and 0.002" shims. The 0.01" shims are too thick but the .002"s are working out well. Some lenses take a couple of the .002s. I take a picture at infinity without a shim, add the shim and shoot again. Using the built in comparison feature on the Q I compare the two shots for sharpness. If the shimmed picture is sharper I add another shim and shoot again comparing the shot with 1 shim vs 2. Continue until the lens starts getting soft again and pull out the last shim.
This is especially important for lenses that are fixed focus such as the Pentax 4.8mm and Sigma 6.5mm.
This also seems to improve the lens performance as well. I have a Pentax 6mm f1.2 lens that is actually focused at infinity at around 0.8' on the dial. It has a lot of focus shift as you stop it down. When I shimmed this lens so that infinity matches up the focus shift is nearly gone when stopping it down. It also makes it a lot easier to zone/hyperfocal focus the lens.
Shims from McMaster Carr.
Shawn