c-mount lenses

B

Barry_Green

Moderator
Got a c-mount lens adapter. I can save you guys a lot of trouble -- don't bother. Unless you're looking for lenses that are about 35mm or longer, the vignetting is pretty nasty.

2X Digital Zoom gets rid of the vignetting, but costs you half your horizontal and half your vertical res. And you can't use the enhanced optical zoom in movie mode, so... meh.

Anyone want to buy a GH1->c-mount adapter? :D
 
I am having a hard time finding consistent info on c-mount lenses but get conflicting info about image circle sizes at different focal lengths. Most I have read say it vignettes at 22mm, but some of the info I read was probably originally written for the G1, which I think has a slightly smaller sensor. What specific lens are you using?

I have a canon c-mount tv zoom lens f2 17-117mm. I wouldn't mind sacrificing the 17-35mm range for some decent lowlight telephoto shots but I am a bit wary of getting the adapter only to find that it won't be useful.
 
I'll take it if your selling for a bargain...

I agree that Panny needs to allow the optical zoom function for just this issue... and hold some hope that they will possibly make that happen.

On the other hand, I feel the c-mount is a wonderful avenue for great results on the m4/3 format. The quality and speed of this glass is really worth while for the workarounds. The stealth factor is unbelievable as well. People think your holding a toy camera.

Switar 26/1.1 (uncropped):
P1170599-vi.jpg


Schneider 16/1.4 (uncropped)
P1100064-vi.jpg


Schneider 25/2 (uncropped)
P1140665-vi.jpg
 
Yes, the vignetting is quite severe. However, for still images, it's kind of a cool effect. Also, here's an idea I had, tell me if I'm crazy: Shoot in 1080p and crop the image a bit in post to eliminate the vignette, then drop into a 720p timeline. It should look just fine while retaining most of the image. Plus, there's just something fundamentally great about buying a 12.5mm f1.4 for $24.00!

Here's a 25mm Switar a friend gave me. It's pretty sweet.

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Barry_Green said:
Got a c-mount lens adapter. I can save you guys a lot of trouble -- don't bother. Unless you're looking for lenses that are about 35mm or longer, the vignetting is pretty nasty.

2X Digital Zoom gets rid of the vignetting, but costs you half your horizontal and half your vertical res. And you can't use the enhanced optical zoom in movie mode, so... meh.

Anyone want to buy a GH1->c-mount adapter? :D
Click to expand...

How much you want for it? I'll take it for sure.
 
I saw a warning on one of the adapter pages stating that c-mount lenses with a rear length protruding more than 3mm (?) may scratch the sensor.
 
j said:
Any fear of c-mount lenses scratching the sensor?
Click to expand...

I don't think so. I was worried about that, too. In any case, what you do is attach the lens to the adapter first...then when you attach the adapter, you can more easily tell that the distance between the sensor and the lens is safe.
 
Barry_Green said:
Got a c-mount lens adapter. I can save you guys a lot of trouble -- don't bother. Unless you're looking for lenses that are about 35mm or longer, the vignetting is pretty nasty.
Click to expand...

Hi Barry, have you tried with Arriflex standard adapters too? It is available on eBay and it is made in Corea, if I remember well. The ARRI standard attachment is the same for 16 and 35mm lenses.
I'm going to buy one also if 35mm lenses should be expensive to buy, but I'm curious to try

Regards

Gary
 
Gary Senda said:
Hi Barry, have you tried with Arriflex standard adapters too? It is available on eBay and it is made in Corea, if I remember well. The ARRI standard attachment is the same for 16 and 35mm lenses.
I'm going to buy one also if 35mm lenses should be expensive to buy, but I'm curious to try

Regards

Gary
Click to expand...

Hey Gary...can you tell me where to find that adaptor? i would be intetrested in that mount.
I just bought a 10mm - 150mm Fujinon AND Canon TV Zoom lens C-Mount.

I wonder how it will look with my GH1...
 
May be a very stupid question but is a 25mm c-mount lens on the GH1 equivalent to 50mm or would it stay 25mm?
 
With the 25mm, it acts as all other lenses that you attach to the GH1...the focal length stays the same, but the field of view is cropped 2x compared to a full-frame 35mm camera. So the 25mm would have the field of view of a 50mm attached to a full frame 35mm SLR. I have a 25mm c-mount lens. It's great but beware there is vignetting in the corners because it was made for a 16mm camera which has a smaller image area than the GH1.
 
this c-mount lens thing is becoming more and more interesting to me but those c-mount lenses are a complete mystery to me. Super8, those tv zoom lenses you are talking about, aren't they meant for 1/3" sensors? what does that mean for vignetting on the GH1 and is it possible to adapt them to it anyway because they have some 4 pin (or 6 pin I dont know) connections to it and I dont know what they're meant for or if you can just ignore them. I just found a 10-70mm 1.4 canon tv zoom lens for about 40 $ on ebay so...would this be working anyway?
 
Longer c-mount lenses (like 35mm and longer) will frequently/usually have enough coverage for the GH1's frame. Shorter lenses will usually mean vignetting, and the shorter, the more.
 
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