Computar ZOOM 1:1.2 / 12.5mm-75mm C Mount Lens

A

alfred

Active member
Is this lens a good lens for the ETC modus? Has somebody experiences with this lens? I am interested, since it is rather fast and a 6x Zoom. Is it sharp by open iris? :happy:Is it recomandable? I could get it for 230 $ rather new. Too much or a bargain?


Thanks Alfred
 
I played with one and couldn't get proper focus through the whole zoom range. I tried a couple different c-mount adapters as well, so I'd say don't bother.
 
Never used that lens but do own the 12.5-75mm 1.8 Pentax C mount w/kipon c adapter and it's a great lens for the GH2. in ETC granted it aint a 12.5 but likely a 44-300?. Love the lens, sharp, great bokeh, does weird things with light, solid build, great focus, had mine declicked. Might be my favorite new lens. Not cheap almost $300 at BH.

this fujinon looks worth a bid, some of the zooms need a slight mod as the c mount needs filing down. My Pentax fits snug on the kipon.
http://cgi.ebay.com/FUJINON-ZOOM-1-...74163137?pt=Camera_Lenses&hash=item3cb759f2c1
 
Rory_B said:
I played with one and couldn't get proper focus through the whole zoom range. I tried a couple different c-mount adapters as well, so I'd say don't bother.
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You need a well done C-mount/micro 4/3 adapter. I have a couple of such adapters tried, which didn´t work, even expensive ones, since the focus measure is not perfect. I have very good results wit ciecio´s adapters on ebay. They are perfect and very stable.

An other reason can be, that the base of lens does not fit exactly into the adapter. Then you have to cut off/file off the edges of the base. - I bought a cheap cosmicar/pentax 25mm/1.4 lens. The lens rasped off the edge of the base works great with the ciecio-adapter. If you have a well made adater, try to file down the edge of the base. Its worth.
 
biginvegas said:
Never used that lens but do own the 12.5-75mm 1.8 Pentax C mount w/kipon c adapter and it's a great lens for the GH2. in ETC granted it aint a 12.5 but likely a 44-300?. Love the lens, sharp, great bokeh, does weird things with light, solid build, great focus, had mine declicked. Might be my favorite new lens. Not cheap almost $300 at BH.

this fujinon looks worth a bid, some of the zooms need a slight mod as the c mount needs filing down. My Pentax fits snug on the kipon.
http://cgi.ebay.com/FUJINON-ZOOM-1-...74163137?pt=Camera_Lenses&hash=item3cb759f2c1
Click to expand...

Thanks for your information. The Pentax is of course a well made quality lens without doubt. I have an Angenieux 2.2/12-120 mm on my GH2. A fine lens, too, which works great. But it is littly bit bulky and I need a bridge for its weight (ca 900g). Fine for tripod use. No run and gun combo. (Too long tele-focus.) So I am looking for a shorter, lighter and specially faster zoom.

The questions is, if the very fast and relatively cheap zoom lenses (cosmicar etc with an aperture of 1.2) are usable in concern of their picture quality?

Thanks for the ebay-link. I am not shure, if I shall spring into the cold water. As long as the item stays cheap no problem, although the shipping (I am living in Germany) and the duties highens the price.

Why have you bought the pentax with an aperture of 1.8 and not with an aperture of 1.2? What were your considerations? Thanks.
 
I have this lens and it works fine. You have to stop down a bit for sharpness/contrast, but otherwise it works fine in ETC mode.

I got a generic c-mount to m43 adapter and it fit perfectly.
 
greeches said:
I got a generic c-mount to m43 adapter and it fit perfectly.
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Can you show me this generic adapter? I have three adapter from various Chinese companies and neither worked because the M4/3 system has a max opening of 38.57mm at a push. A great deal of these older C mount lenses have 46mm bases

These C mount lenses are recessed into the body unlike most other lenses and this is a the issue. If your claiming your adapter works for this Computar lens it cannot be at the correct focal distance for the chip?

You could clear up a lot of trouble if you can show me the exact adapter you are using.
 
Fitting perfectly is one thing, but can you focus properly throughout the zoom? Usually these lenses have problems at the wider angles because the rear mount is too far from the 4/3 sensor, meaning you could only do macro. But at tele mode should be better.
 
greeches said:
I have this lens and it works fine. You have to stop down a bit for sharpness/contrast, but otherwise it works fine in ETC mode.

I got a generic c-mount to m43 adapter and it fit perfectly.
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Nice to read this. How much do you stop down the lens? Is there enough difference to the Pentax 1.8 or Fujinon1.8 with the same zoom ranges?
 
Sun said:
None of these C mounts used for CCTV work unless they are very small 8mm types. You can use the Computar but you will have to cut off at least 10mm from the rear as I have done on a few lenses. These lenses do not fit unless you are willing to do some cutting and gluing basically like I have in this thread.

http://www.dvxuser.com/V6/showthrea...oom-lenses-and-CCTV-lenses-on-the-M4-3-system
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I use the kipon c mount, all my Pentax CCTV lenses work just fine, perfect fit to GH1/2 and AF100. I own 12.5mm 1.2, 25mm 1.4, 12.5-75mm 1.8 all fit. Obvious vignette issues with lenses to GH1 and AF100.
 
alfred said:
Thanks for your information. The Pentax is of course a well made quality lens without doubt. I have an Angenieux 2.2/12-120 mm on my GH2. A fine lens, too, which works great. But it is littly bit bulky and I need a bridge for its weight (ca 900g). Fine for tripod use. No run and gun combo. (Too long tele-focus.) So I am looking for a shorter, lighter and specially faster zoom.

The questions is, if the very fast and relatively cheap zoom lenses (cosmicar etc with an aperture of 1.2) are usable in concern of their picture quality?

Thanks for the ebay-link. I am not shure, if I shall spring into the cold water. As long as the item stays cheap no problem, although the shipping (I am living in Germany) and the duties highens the price.

Why have you bought the pentax with an aperture of 1.8 and not with an aperture of 1.2? What were your considerations? Thanks.
Click to expand...

I bought the lens because I had an account at BHphoto and rarely use ebay as paypal keeps getting hacked! Bought the zoom for GH2 that is on it's way no other reason. It's light, compact perfect everyday lens for grabbing fun stuff. Have used all on fashion shoots to create vintage iris/vignetting look and can say that they are sharp as my Nikon primes. Will post a few grabs later.
 
biginvegas said:
I use the kipon c mount, all my Pentax CCTV lenses work just fine, perfect fit to GH1/2 and AF100. I own 12.5mm 1.2, 25mm 1.4, 12.5-75mm 1.8 all fit. Obvious vignette issues with lenses to GH1 and AF100.
Click to expand...

Did you buy it on eBay? Do you have a link where you bought the kipon adapter? Thanks.
 
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