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Message |
    
Ismaelg
Tinkerer
Username: Ismaelg
Post Number: 23
Registered: 11-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, December 11, 2009 - 03:04 am: | 
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Hi,
I recently acquired a Pentax SV with the Supertak 55mm f1.8 lens. It is my best looking best feeling camera. I took it out for a spin and I'm noticing some focusing issues. Looking thru the viewfinder, "infinity" is about 15-20 feet away, but beyond that it is never in proper focus. I took this series of test shots and the only useable pictures are those at f11 or f16. Below that I'm not getting proper focus.
1/125 f16
http://images51.fotki.com/v1550/photos/4/1233394/7801733/12760025-vi.jpg
1/250 f11
http://images112.fotki.com/v1532/photos/4/1233394/7801733/12760026-vi.jpg
1/500 f8
http://images52.fotki.com/v1551/photos/4/1233394/7801733/12760027-vi.jpg
1/1000 f5.6
http://images49.fotki.com/v1556/photos/4/1233394/7801733/12760028-vi.jpg
I don't have equipment to test for accuracy, but the shutter speeds seem to be ok and consistent with other cameras.
I don't have any other M42 body or lens right now (will fix that soon  ) that I could do some additional testing, but it seems to me it should be in the lens, not the body.
Could this be an adjustment issue on the lens? If so, how can I proceed? Both the lens and the body look pristine with no obvious signs of repairs.
Can somebody point me in the right direction?
Thanks,
Ismael |
Chiccolini
Tinkerer
Username: Chiccolini
Post Number: 69
Registered: 06-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, December 11, 2009 - 03:51 am: |
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The only thing that comes to mind is the mirror may not be seating properly and may be a mm or so off. See if the mirror is loose or something like that.
The first thing I thought was the footage scale on the lens had come loose and was misaligned. I had a lens like that. The band with the footage/focusing numbers had come loose and was moving around every time I focused. I gave it a quick fix by setting the lens to infinity and nudging the number dial along until it hit infinity, then instant glued it in place. A quick fix but better than disassembly. And I must say I was surprised because I was sure Pentax engraved those numbers onto the metal but, maybe, this was a later lens and they decided to go the cheaper method. |
Steve_roberts
Tinkerer
Username: Steve_roberts
Post Number: 38
Registered: 07-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Friday, December 11, 2009 - 06:21 am: |
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Ismael,
This sounds very much like Chiccolini's post and also a problem with a Pentax KM that I posted notes about on 6th Nov 2009. My stuff turns up if you search under "Pentax Mirror".
Best wishes,
Steve |
Ismaelg
Tinkerer
Username: Ismaelg
Post Number: 24
Registered: 11-2009
Rating: N/A
Votes: 0 (Vote!) | | Posted on Saturday, December 12, 2009 - 10:52 am: |
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UPDATE:
I got a hold at a Spotmatic with a Helios 44 lens and did a lens swap test. The issue followed the lens so the body seems to be innocent.
A fellow pentaxian gave me the procedure to adjust this lens to infinity and I'll try that soon. I'll post the process and the results later.
Thanks,
Ismael |
Kennym
Tinkerer
Username: Kennym
Post Number: 9
Registered: 01-2010
Rating: N/A
Votes: 0 (Vote!) | | Posted on Tuesday, January 19, 2010 - 05:43 pm: |
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look at the lens,turn it to infinity,is the infinity mark split by the red diamond on the focus scale? if not the lens needs adjusting,i would say the lens has been stripped down before you got it,and not been put back together properly,hope this helps. |
Jcfn
Tinkerer
Username: Jcfn
Post Number: 8
Registered: 09-2006
Rating: N/A
Votes: 0 (Vote!) | | Posted on Thursday, March 04, 2010 - 01:21 am: |
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Probably mirror seating at the correct angle. The mirror rester behind the mirror, for want of a better description, has a rubbery ring round it which becomes compressed over time. One poss remedy is to turn this little rubber ring until the compressed side faces away from the back of the mirror. I am curious to know how one can adjust this accurately. I have a S1a which has the same issue |
