I've found a C mount lens calculator+looking for 0.95

S

seb33

Well-known member
I've found a C mount lens calculator :

http://www.graftek.com/lensselect.php

Does anyone know how it works ? What is the size of GH1 sensor ?
I'm looking for a 25mm fast c mount lens, like 0.95
one which did not need machining, and cover the sensor without too much vignetting, and all this for cheap !!! (Yes I still believe in Santa Klaus !

I found the Senko 25mm 0.95 for 307$, does anyone know if it needs machining to fit to C mount adapter ? Does it focus to infiny ?

THANK YOU
 
barry is stating that the sensor is bigger than listed so you won't or will unlikely find any matches from that calculator. or so i think thats what he is getting at.
 
Well, yes, but also I knew about the custom size option; I was pointing out that of the choices they had listed, none were anywhere near appropriate. I should have said "you'd have to type in the 18x10.125 in the custom size" box... ;)
 
MR Fanny said:
barry is stating that the sensor is bigger than listed so you won't or will unlikely find any matches from that calculator. or so i think thats what he is getting at.
Click to expand...
Yes, but you can add your own size of sensor, when you choose "non standard" in "CCD SIZE", you can type the right size (18mm x 10.125mm) then you'll have answers....... :)
 
I have a Senko 25mm f/0.95 on my GH1 with an RJ adapter.

- Had to file the focus ring down 3-4mm for it to fit. This involves taking apart the bottom part of the lens, so you have to be careful about marking where the focus ring originally clamped down

- There is some vignetting in the corners. Also, there is considerable amount of barrel distortion, which can be good for people/vintage/artsy shots but bad in other cases. If you postprocess to correct for the distortion, you actually end up cancelling out much of the vignetting!

- If you put any filters on (40.5mm front thread), they will worsen the vignetting. I have a very makeshift solution of a 43mm->55mm step-up ring that I snugly fit onto tape wrapped around the outside of the lens.

- The lens flares VERY easily. And on top of that, the inside part of the barrell is fairly shiny.

- The lens is quite sharp, even towards the edges. But then again I'm no expert.

- Even having this lens, I'm still going to get the panaleica 25mm f/1.4.
 
seb33 said:
Yes, but you can add your own size of sensor, when you choose "non standard" in "CCD SIZE", you can type the right size (18mm x 10.125mm) then you'll have answers....... :)
Click to expand...


so did yo get answers? cause i didn't. maybe i'm missing something.
 
Did anyone manage to find a lens in wide angle that would work i.e. 6-12mm size using the calculator ? I dont really know what to enter for the values.
 
C-mount lenses designed for 1" machine vision cameras will cover GH1 at wide angles. 16mm film lenses or 2/3" industrial lenses typically won't.
 
I filed the chrome mounting ring of the Cosmicar 12.5mm f1.4 down to the top of the set screw holes. I also had to grind down the right-angle inner ridges of a C-mount adapter to match. You don't need a thin profile adapter, but its inner ridges will need to be filed.

The resulting lens vignettes in the GH1's "L" Picture Size mode. If you enable the "EZ Extended Optical Zoom" mode, you can set the camera to the "Mez" Picture Size. That will zoom in and crop out the vignetted corners in-camera, giving you a 6 mega-pixel photograph. (You could also crop the L size picture yourself in post-production.)

I have yet to find a C-mount lens that was suitable for video, though you could use it for an antiquated vignetted look.
 
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Im interested in the Senko 25mm 0.95 for the odd things it will do. It's C mount will not adapt to my m4/3 C mount? What is an RJ adapter?
 
I have the kipon c t0 m43 should work. Yes, your stuff is particularly beautiful. The 0.95 you own that? Kinda expensive as a startup experimental lens. You have a suggestion for top 5 el cheapo CCTV lenses?
 
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