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08-31-2011, 11:43 AM   #1
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645: Inconsistent shutter speed - SOLVED: Development Issue !


When I shoot with my 645 I observed constantly a darker area at the left side of all shots.
Has anybody have an explenation. For me it looks like the shutter is to fast at the first or last distance of its way.

Further the total shape is not perfectly rectangular - is this normal for a 645?

What can I do against it?

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Last edited by klaus123; 09-01-2011 at 12:59 PM.
08-31-2011, 12:13 PM   #2
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No, this definitely isn't normal. Looks like there may well be something wrong with the shutter mechanism. I'm not sure if anyone can still fix this, but then again, used 645's are very cheap these days, especially without the lens.

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08-31-2011, 05:04 PM   #3
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If I am not mistaken, the Pentax 645 shutter is a vertical focal plane shutter moving from top to bottom. This might be a light leak. How are the seals on the back?

Last edited by Yamanobori; 08-31-2011 at 06:41 PM.
08-31-2011, 05:50 PM   #4
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The negative is rendered positive so dark area is dark shadow. There are no distinct edges and the part of the dark area conforms to the edge of the plane. The contrast differences are narrow and the shape is much like a feathery almost multi-circle pattern cast at close range? Did you inspect the shutter running a speeds of 1/2 or 1 second to look for a chance of a fray or foreign material stuck to the leading edge of the curtain or in the mirror box under the mirror a dangling piece of foam?

from the perspective looking from the back of the camera while the picture was taken.

Last edited by MysteryOnion; 08-31-2011 at 06:04 PM.
09-01-2011, 09:33 AM   #5
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If by "not totally rectangular" you mean the little "tabs" at the corners, then this is normal. If you mean that the image is slightly tilted, then yes, I've also seen that on some frames from my 645N and have tried to work out what it is..
09-01-2011, 09:58 AM - 1 Like   #6
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While I don't have a 645 without film in it handy to check, I'm also pretty sure the shutter goes the other way. So I would bet this is a development problem. (The shadowed (less developed) bit at the top, and not enough developer in the tank, maybe?)
09-01-2011, 11:22 AM   #7
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I think, the level of developer can be excluded as I have seen the effect secaral times, but only shooting 645 Films - the 6x7 Films interim have been ok and especially the sample was from a cycle, where I developed 2x645 & 1x135 +1x67 in 3 spindles in a Jobo 1000 Tank with 1 Liter of Kodak D76/1+3 - and the effect was on both 645 Films which had been in different spindles.

Further I would assume, that the counter marking would be a little bit brighter.

I think I will do some test shots with ten remaining pictures on the film that is in currently using different aperture settings to evaluate, what is influencing the effect and than (w/o film in) have a look inside the camera.
09-01-2011, 11:42 AM   #8
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The film is taken of and I had a look into th cam with a tortch at 15 sec and B - nothing specific I could find so far :-(

09-01-2011, 12:36 PM   #9
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I tock 2 fotos from the front with a ring-flash - sync time 1/125 and 1/60
The shutter is definitive vertical but still no clue for the effect.....
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09-01-2011, 12:57 PM   #10
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Solved .....

I double checked the development tank with the 3 spindles and 1 liter of water ....drougge: You have been right !

Thank you for your help

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