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05-11-2013, 03:10 PM   #1
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My favorite C-mount lenses so far

I started with the old manual Pentax/Cosmicar C-mount lenses, and while they are good, once I discovered the Fujinon (Fuji Photo Optical Co.) C-mount lenses, I was hooked. I now have six:

5.5mm f/1.6
16mm f/1.4
25mm f/0.85
35mm f/1.7
50mm f/1.4
75mm f/1.8

Equivalent focal lengths on full-frame would be 30mm, 88mm, 137mm, 192mm, 275mm, and 412mm. The number of aperture blades is 6, 6, 8, 6, 10, and 10 respectively. Front filter threads are 52m, 43mm, 52mm, 43mm, 49mm and 49mm respectively. With the Q adapter attached, Their physical lengths are approximately 2", 1.75", 2.1", 2.1", 3.25", and 4" respectively. Some of them have recessed front elements that essentially creates an integrated hood. Distance markings on the focus rings are in feet and meters. Lettering is engraved and the engraved area is painted in (so no paint on flat surfaces that can rub off).

What I like about them is their optical quality, build quality, and design. They are entirely metal, with integrated ridges for the focus and aperture rings. Focusing is well-damped and for most of the lenses have a good long throw. Unlike many C-mount lenses, the aperture rings have specific stops and closes down as you turn it to the right (unlike some lenses which go the other way). The aperture ring is also closest to the lens mount, except in the 75mm lens (many C-mount lenses have the aperture ring farther out, past the focus ring). I bought C-mount adapters (the kind that have three screws to adjust rotational alignment) and rear lens caps for each lens, so they are easy to change as any Q lens. I bought microfiber sunglass drawstring bags for each of the lenses and can fit them in a 5" x 5" x 9" camera bag along with the Q, a couple more lenses, and some accessories, which is impressive.

Unfortunately, I haven't had much time to go out and photograph lately, so I don't have much to share in that regard, but I've been happy with the shots I've taken so far. In general, I'd characterize all the lenses as somewhat soft fully open, and then they sharpen up a stop or two down. Colors are good. When dialed in, the in-body shake reduction works very well. As a fan of manual focus and available light photography, I find them a joy to use on the Q.

05-11-2013, 03:55 PM   #2
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Join Date: Nov 2011
Location: Northeast USA
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Would love to see some photos of your C-mount lenses on the Q and photos taken with the lenses
Also, where do you get your 3 screws-adapters?
05-11-2013, 04:05 PM   #3
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Location: Iowa
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Nice! My wife has this Computar that I picked up as a BIN on eBay for $20. It's pretty decent out to 25mm or so. Past that it gets soft quick. It also does macro.

I'd like to find a nice, fast "normal" prime around 8mm. Most of those I find have a fixed iris, or are stupid expensive.
05-12-2013, 05:49 AM   #4
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I have a Pentax 3-8mm f/1 zoom I have been using for wide angle. It is a CS mount, but with some shims I could get it into the inside of the C mount to Q adapter. (The one with the removable inside). It isn't the greatest lens, and vignettes below about 5mm, but is fun to play with. Mine doesn't have aperture or focal length markings, just levers that slide back and forth, so I tend to leave SR on at 3 or 4mm. I'll try to get some pictures to share as well.


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