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Spotmatic
Joined: 18 Aug 2008
Posts: 4045
Location: Netherlands
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 Posted: Thu Sep 17, 2009 7:14 am Post subject: Pentax 645 intermittent problem |
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Spotmatic wrote:
The Pentax 645 I bought appears to have a problem 
Basically, it appears that in P mode there is a 50% chance that the camera selects the smallest f/stop (f/22) during exposure, even though the camera shows a much larger f/stop in the viewfinder. So, at least 50% of the pictures are badly underexposed (near black). If the camera does not select f/22 all by itself, then the shots are perfectly exposed.
The lens does not seem to be a problem, as all lenses I tried behave the same. So it must be on the body side.
Any ideas? Is there a communication problem between the lenses and the body?
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Peter - Moderator
Pentax K-5 + Pentax 645 + Canon 5D + Bessa RF 10,5cm Heliar, and a 'little' bag full of MF lenses. The lens list is * here *.
My fast 80s: Asahi-Kogaku Takumar 83mm f/1.9 - Super-Takumar 85mm f/1.9 - FA 77mm f/1.8 Limited - Cyclop 85/1.5 (Helios-40 innards) - Komura 80mm f/1.8 - Meyer Görlitz Primoplan 7,5cm 1:1.9 - Carl Zeiss Jena 80mm f/1.8 Pancolar - Canon 85mm f/1.8 S.S.C. - Canon 85mm f/1.2 S.S.C. Aspherical |
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CarbonR
Joined: 31 Dec 2008
Posts: 1969
Location: Clermont-Ferrand, France
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| Posted: Thu Sep 17, 2009 9:36 am Post subject: |
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CarbonR wrote:
Are you sure it select f/22 and not a too much high speed ? Sometimes my K100D has this problem (altough the speed on external screen is right) and I got beautiful black shots 
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Cameras : Canon 5D, Pentax K100D, Pentax 6x7, Spotmatic
Lenses : 15mm to 1000mm (24x36)
My websites : [FR & ENG]Takumar - the eyes of the Spotmatic : info about all Takumar lenses // Kogaku - My photo site
I am selling : Takumar lenses and rare Pentax bodies, pm me if you're interested in something [MFLenses feed-back]
Information on Takumar lenses with samples :
Wide angle : Takumar 15/3.5 15mm, Takumar 17/4 17mm, Takumar 18/11 18mm, Takumar 20/4.5 20mm, Takumar 24/3.5 24mm, Takumar 28/3.5 V1 28mm, Takumar 28/3.5 V2 28mm, Takumar 35/2 V1 35mm, Takumar 35/2 V2 35mm, Takumar 35/2.3 35mm, Takumar 35/3.5 35mm, Takumar 35/4 35mm
Standard : Takumar 50/1.4 V1 50mm, Takumar 50/1.4 V2 50mm, Takumar 50/3.5 50mm, Takumar 50/4 50mm, Takumar 55/2 55/1.8 55mm, Takumar 55/2.2 V1 55mm, Takumar 55/2.2 V2 55mm, Takumar 58/2 58mm, Takumar 58/2.4 58mm
Short tele : Takumar 83/1.9 83mm, Takumar 85/1.8 85/1.9 85mm, Takumar 85/1.8 85mm, Takumar 100/2 100mm, Takumar 100/3.5 100mm, Takumar 100/4 100mm, Takumar 105/2.8 V1 105mm, Takumar 105/2.8 V2 105mm, Takumar 120/2.8 120mm
Telephoto : Takumar 135/2.5 V1 135mm, Takumar 135/2.5 V2 135mm, Takumar 135/3.5 V1 135mm, Takumar 135/3.5 V2 135mm, Takumar 150/4 V1 150mm, Takumar 150/4 V2 150mm
Long tele : Takumar 200/3.5 200mm, Takumar 200/4 200mm, Takumar 200/5.6 200mm, Takumar 300/4 V1 300mm, Takumar 300/4 V2 300mm, Takumar 300/4 V3 300mm, Takumar 300/6.3 300mm, Takumar 400/5.6 400mm, Takumar 500/4.5 500mm, Takumar 500/5 500mm, Takumar 1000/8 V1 1000mm, Takumar 1000/8 V2 1000mm
Zoom : Zoom-Takumar 45~125/4 , Zoom-Takumar 70~150/4.5 , Zoom-Takumar 85~210/4.5 , Zoom-Takumar 135~600/6.7
Achromatic : Ultra-Achromatic-Takumar 85/4.5 , Ultra-Achromatic-Takumar 300/5.6 300mm |
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Spotmatic
Joined: 18 Aug 2008
Posts: 4045
Location: Netherlands
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| Posted: Thu Sep 17, 2009 9:41 am Post subject: |
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Spotmatic wrote:
| CarbonR wrote: |
| Are you sure it select f/22 and not a too much high speed ? Sometimes my K100D has this problem (altough the speed on external screen is right) and I got beautiful black shots |
No, I actually made a few self portraits to see the diaphragm close, and I saw that it closed completely.
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Peter - Moderator
Pentax K-5 + Pentax 645 + Canon 5D + Bessa RF 10,5cm Heliar, and a 'little' bag full of MF lenses. The lens list is * here *.
My fast 80s: Asahi-Kogaku Takumar 83mm f/1.9 - Super-Takumar 85mm f/1.9 - FA 77mm f/1.8 Limited - Cyclop 85/1.5 (Helios-40 innards) - Komura 80mm f/1.8 - Meyer Görlitz Primoplan 7,5cm 1:1.9 - Carl Zeiss Jena 80mm f/1.8 Pancolar - Canon 85mm f/1.8 S.S.C. - Canon 85mm f/1.2 S.S.C. Aspherical |
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cilinderman
Joined: 13 Dec 2008
Posts: 317
Location: Canillo, Andorra
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| Posted: Thu Sep 17, 2009 1:43 pm Post subject: |
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cilinderman wrote:
Mmmmm... are you speaking when the diaphragm ring is in the "A" position right? Are you sure it's correctly fixed in that position? Have you tried with other Pentax 645 lens?
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5D & Fujica ST801|| Carl Zeiss Planar MM 50/1.7 (departed for resurrection) || Carl Zeiss Distagon 28/2.8 AEJ || Meyer Orestor "Pentacon" (relabeled) 135/2.8 || Carl Zeiss Jena 135/3.5 || Carl Zeiss Sonnar MM 85/2.8 || Carl Zeiss Flektogon MC "White" 35/2.4 || Olympus Zuiko OM MC 21/3.5 || Super Takumar 55/1.8 || Rollei Planar HFT 50/1.8 || "The three tenors" from Orio (Nikkor pre-AI 85/1.8, 135/3.5 & 105/2.5) |
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Nesster
Joined: 24 Apr 2008
Posts: 5883
Location: NJ, USA
Expire: 2014-02-20
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| Posted: Thu Sep 17, 2009 1:44 pm Post subject: |
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Nesster wrote:
My suspicion is along those lines - the mount sensor for aperture setting may be sticky on the camera, or otherwise unable to sense the lens is set to A instead of f/22.
Erm. Replace "sticky" by "bad electrical contact",,, Try cleaning the contacts on the camera mount - as the problem occurs on multiple lenses, unless they all are dirty in the same way, it's probably the camera.
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-Jussi
Camera photos
Print Photographica
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Spotmatic
Joined: 18 Aug 2008
Posts: 4045
Location: Netherlands
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| Posted: Thu Sep 17, 2009 1:53 pm Post subject: |
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Spotmatic wrote:
Thanks! Yes, the lenses are in "A".
I'll try to clean the contacts and report back my findings.
_________________
Peter - Moderator
Pentax K-5 + Pentax 645 + Canon 5D + Bessa RF 10,5cm Heliar, and a 'little' bag full of MF lenses. The lens list is * here *.
My fast 80s: Asahi-Kogaku Takumar 83mm f/1.9 - Super-Takumar 85mm f/1.9 - FA 77mm f/1.8 Limited - Cyclop 85/1.5 (Helios-40 innards) - Komura 80mm f/1.8 - Meyer Görlitz Primoplan 7,5cm 1:1.9 - Carl Zeiss Jena 80mm f/1.8 Pancolar - Canon 85mm f/1.8 S.S.C. - Canon 85mm f/1.2 S.S.C. Aspherical |
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