| Author |
Message |
    
Pilkis
Tinkerer
Username: Pilkis
Post Number: 1
Registered: 04-2007
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, April 26, 2007 - 07:08 am: | 
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Hello,
I'm searching for replacement of cracked back glass. Problem:
http://update.ktu.edu/images/IMG_2993.jpg
Lens:
http://update.ktu.edu/images/IMG_2991.jpg
http://update.ktu.edu/images/IMG_2987.jpg |
Jan
Tinkerer
Username: Jan
Post Number: 30
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, May 01, 2007 - 06:45 pm: |
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This looks like a lens made in Japan, probably by Cosina? It will be nigh impossible to find a replacement element; as the lens has an M42 mount, I would recommend to buy a used Pentax Super Takumar. Available as f:1.8 and f:1.4, both excellent performers, definitely better than the Porst and ridiculously cheap on eBay.
All the best,
Jan |
Peterw
Tinkerer
Username: Peterw
Post Number: 4
Registered: 12-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, June 22, 2007 - 03:29 pm: |
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Porst didn't make anything themselves, though they may have commissioned some. They were a retail organisation using Porst as the brand name for cameras made by a wide variety of makers.
I agree with Jan that it just isn't worth trying to get a new rear element. It would cost more than a decent secondhand M42 lens.
I notice there doesn't seem to be an automatic iris stop-down pin on your lens. If your camera doesn't have auto stop-down, and you haven't already got another lens, make sure it is either pre-set or has a manual stop-down feature.
I don't know where you are, but if you are in Europe you've got a wide choice of good M42 lenses. Zeiss and Meyer are two names that come to mind, but don't overlook the Russian Helios lenses for the Zenit. In my experience they give first-class results, and they go on ebay for peanuts - often with a Zenit camera as a rear lens cap. LOL.
Peter |
Turnergande
Tinkerer
Username: Turnergande
Post Number: 16
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, June 22, 2007 - 05:54 pm: |
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From what I have read, Tomioka produced the optics for several brands of 55mm f1.4 M42 lenses; Cosina, Chinon, Sears, Yashica and maybe even Mamiya. That is not to say those companies did not make many of their own lenses. I compared my own above listed f1.4 lenses with that Porst lens and they all look quite the same. If one looks closely there is a stop down pin on that Porst. The only practical way change that cracked rear cell is to find a 'beater' and try to swap. Some of the collectors & repairers collect a lot of these old bits & pieces. One can also unscrew the name ring and swap it with another equivalent lens if the name brand is important enough to match it up with the Porst badged camera. |
Turnergande
Tinkerer
Username: Turnergande
Post Number: 17
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, June 22, 2007 - 07:01 pm: |
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I should add the Rikenon 55mm f1.4 to the above list and scratch the Yashica. The Yashica Yashinons, although made by Tomioka, apparently did not include a 55mm f1.4. Yashica's normal lenses are typically 50mm. Yashica as many of us know, eventually acquired Tomioka. |
