C-Mount lens: the hunt begins anew

Lens12-27A.jpg
 
Certainly all lenses up to 25mm will not work due to the fact that these are RX lenses, which have a slightly different back focal flange for the Bolex prism in the RX cameras. From 25mm and up you might get away with the difference, but it is still a guess if you'll be able to achieve perfect focus on infinity.
 
I hope this isn't too far off topic...

I hope this isn't too far off topic...

Because I've found an old Canon L1 with the VL mount. I want to know if that mount is completely incompatible with the G-series u4/3 mount?

Shingoshi
 
After further reading...

After further reading...

Am I correct about this? The G-series has a 22mm image circle with a 20mm flange distance. The VL lenses are for 1/2" sensors, which I'm now guessing are way too small to cover the 4/3 sensor. Am I correct now that I've read more about this? I thought I saw a Voitlander adapter for VL. But that may be a completely different system.

Shingoshi
 
Hello Mr Fanny !

I have the same lens as you but I can get things in focus. Could you tell me where (exact saler) you bought your adapter since I believe mine doesn't fit this lens ?
Thanks !
 
have you made sure the reason why your lens does not focus is because it may need modifying? I got my adapter from jinfinance on ebay, the thinner one with silver rim. Have yet to find a bargain c-mount to test it though.
 
I have several c-mount lenses and the ALL vignette more or less. The worst vignetting is the Computar 8.5mm 1:1.3 and using the zoom factor doesnt really satisfy me. Somehow the 2x zoom factor doesnt give me 17mm 1:1.3 but a lot more!
The Schneider Xenoplan 17mm 1: 1.7 is already a bit better vignetting wise.
My preferred at the moment is the Cosmicar 12.5 mm 1:1.4.
I also got an Angenieuex zoom 12-120mm which gives a very peculiar image, sort of old-fashioned.
I am still looking for the right & fast wide angle lens....a lot of times the original 14-140 is still the best.
 
Last edited:
From Wikipedia: "CS-mount has a flange focal distance of 12.52 millimetres (0.493 in), and is otherwise identical to the C-mount."

(C-mount has a flange focal distance of 17.526mm.)
 
at the risk of answering my own questions, is there an obvious difference in quality from a modern day CCTV lens compared to an old school 16mm lens? You can buy these CCTV lens new and they don't cost a million bucks.
 
will a zoom c mount , lets say 12-70mm , have dark corners at all field of view or just between 12-25mm? thanks
 
I´ll have to throw in another question:

If a cs mounted lens is 5mm closer to the sensor than a c-mounted, will this help with vignetting or is it the other way around. I believe it should help but some knowing would be much apreciated.

Because: This lens I linked to is actually a zoom lens from 2,8mm to 12mm with F1,3.

That would really rock....insanely! :)
thanks!
 
I just read on some ebay thing for CCTV lenses that CS mounts wont work properly on c mounts but C mounts will work on CS mounts if that contributes anything to the discussion. Not sure if it applies to cmount gh1 adapters or not though.
 
If you mount a CS mount lens on the GH1 adapter you will have a macro lens only - the 5mm smaller flange focal difference means you will not get anywhere near infinity (or even normal) focus. Also, the CS mount lenses are generally for smaller sensors - the one linked above is for a 1/3" sensor so would have very little coverage at all.
 
Well, a bit about Tevidon lenses on a GH1. ALL of tehse needs teh mount converted since they do not fit the now available micro 4/3 c-mount adaptors ("jinfinance" etc.). Further there are two types of Tevidon mounts: a) c-mount version (needs conversion), b) a bajonet version (needs a even more complicated conversion, c) the ones I have converted (ready to be used...LOL)

From me experience using them on a GH1, let me summarize my findings:
10mm: massive vignetting
16mm: substantial vignetting
25mm: some corner vignetting
35mm: no vignetting
50mm: no vignetting
70mm: no vignetting
100mm: no vignetting
IF and ONLY IF used with an appropriate adaptor which fits into the
commercially available c-mount adaptors (yes, you need two!!)

I have made these needed adaptors and I have a few Tevidons
converted here, just in case there is some interest....

A few shots to prove how great these little gems are...

f1.4/25mm (shot fully open) - this focal length vignettes a bit:

455_P1020311_c_1.jpg


455_P1020335_c_1.jpg


455_P1020353_c_1.jpg


455_P1020361_c_1.jpg


455_P1020368_c_1.jpg


455_P1020341_c_1.jpg


455_P1020329_c_1.jpg


great sharpness + contrast, very creamy bokeh!!

more later about the 35, 50, 70, 100mm versions...

...and yeah, HAPPY THANKSGIVING TO EVERYONE!!
 
This now about the Tevidon 1.9/35mm, also converted by me.

So let's start the show. All shot using a Lumix GH1, in full format, fully open except otherwise noted.

455_TV35mm_P1020714a_c_1.jpg


100% crop
455_TV35mm_P1020714c_c_1.jpg


455_TV35mm_P1020734a_c_1.jpg


100% crop:
455_TV35mm_P1020734c_c_1.jpg


455_TV35mm_P1020828a_c_1.jpg


100% crop:
455_TV35mm_P1020828c_c_1.jpg


455_TV35mm_P1020802a_c_1.jpg


100% crop:
455_TV35mm_P1020802c_c_1.jpg


455_TV35mm_P1020751a_c_1.jpg


100% crop:
455_TV35mm_P1020751c_c_1.jpg


Bokeh shots:
455_TV35mm_P1020773c_c_1.jpg


Xmas lights are great for that..
455_TV35mm_P1020876_c_1.jpg


personally I'm very happy with the results....and not a bit vignetting.
 
Last edited:
You must log in or register to reply here.
Back
Top