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How to move aperture?
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PostPosted: Thu Jan 31, 2013 1:44 pm    Post subject: How to move aperture? Reply with quote

Hi!
I have a Tamron Television 4mm F1.2 with C-Mount
http://www.ebay.de/itm/190781974404?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1497.l2649
The aperture seems to be only contrable via electronic cable control - it's stuck at F32 or above
Any idea how to move it?


PostPosted: Thu Jan 31, 2013 2:03 pm    Post subject: Reply with quote

Moin!

Would this document put you in the right direction?
https://www.tamron-usa.com/cctv/prod/assets/pdfs/OM%20IR%20v2%20256.pdf
also see other docs on that site.

MfG


PostPosted: Thu Jan 31, 2013 4:29 pm    Post subject: Reply with quote

It will need control electronics. Forget it, no sense in having a diy box of electronics just to control the aperture. I have several Computar CS mount lenses with electronic apertures, they are useless unless mounted on a cctv camera with electronic aperture control socket to plug their control lead into.

You are aware it is a CS mount lens, not a C mount and has a 5mm shorter register so can't be used without surgery to either lens or adapter?

I'm sorry, you bought the wrong lens.

There are some fairly nice Tamron c mount lenses, I had a 4.5mm fisheye that was interesting.





Last one is a 100% crop from the NEX-3, in common with most of these CCTV lenses, it's crappy IQ, low resolution, probably no more than 20-25lp/mm. I tried a dozen or more C mount lenses and only found one that had acceptable IQ, that was a machine vision lens that had been very expensive when new, all the CCTV ones were crap, which is to be expected as they only have to record 400-600 lines which is very low resolution compared to any digicam.