Pentacon Six not exposing whole frame!?

[Mammoth_research]

Hello you lovely people,

I just developed the first test roll from my new pentacon six tl. The frames are not square... they are cut off. I WILL TAKE PICS WHEN NEGATIVES DRY

It seems like there is fogging in the area that is cut off, so some light must have gotten to the film. The rest of the frame looks good across the whole roll - at least at first glance.

What might be going on here? I know about all the spacing issues people complain about, but here the spacing is very good. The shutter sounds decently accurate, but maybe I need to looks at the curtains... or maybe the mirror? And yes, I used the right amount of developer in my dev tank.

Thanks very much

 

[abruzzi]

sounds like shutter capping. Does the Pentacon have a focal plane shutter? Cameras with FP shutters have two curtains. Both curtains need to run at the same speed, If the leading curtain runs a little too slow, the trailing curtain catches up and for the rest of the travel the shutter is closed.

 

[Eff64]

This is a visual medium

 

[Mammoth_research]

This is a visual medium

Somebody put this guy down for least helpful comment of 2024! I will add pictures later today, time got away from me last night

 

[guangong]

This is a very common problem for Pentacon cameras. Years ago I was presented with a Pentagon camera by the factory and even that camera had a problem with film advance. As I understand, it can be fixed. Very capable, but unreliable, picture takers with fine lenses.

 

[Sanug]

I understand the problem not with the film advance. There must be something wrong with the shutter curtains run.

Did you encounter the problem at maximum shutter speed, or are slower speeds effected?

I had some Asahi Pentax Spotmatics with the same issue at 1/1000s and 1/500s. The Pentacon six has a similiar horizontal running shutter with curtains.

 

[guangong]

Re-reading the post, probably a focal plane shutter problem, although be prepared for a film advance problem sooner or later.

 

[reddesert]

Pictures would help a lot. I know you said you pictures would come along, but when asking for free advice, can't blame people for pointing this out. For example, we don't yet know which direction your photos are cut off in. One direction suggests a shutter problem, and the other a mirror problem.

 

[outwest]

Mine did this and it was a curtain problem and my tech fixed it.

 

[loccdor]

I have two Pentacon Six's. One of them had a similar uneven exposure shutter problem that was fixed with a CLA (cost more than the camera). However, *both* cameras had overlapping frame issues which are *not* fixed by CLA. This is why I now use the Pentacon Six lenses on a Mamiya 645.

 

[Mammoth_research]

Here's a picture finally. As you can see, the frame is cut off at what would be the bottom of the frame. There is a little bit of light on the cut off area.

 

[dirbel]

Ok, it's not shutter that causes the problem. The shutter is running before the mirror is completely out of the way.

 

[Mammoth_research]

Ok, it's not shutter that causes the problem. The shutter is running before the mirror is completely out of the way.

Gotcha, thank you for the help. So I guess if the mirror action was cleaned and lubricated I would be ok? This makes a lot of sense because the exposure seemed pretty spot on, therefore unaffected by sticking shutter

 

[dirbel]

Well, it's strange. I thought there is an interlock between the start of the shutter and the mirror position. I don't have a camera here to check though.

 

[MattKing]

That is a really sharp demarcation for it to be a problem with the mirror movement.
Is there something in the film gate?

 

[outwest]

As loccdor said, I gave up on the various problems that popped up with the Pentacon 6 and use the great lenses (with adaptor) on a Mamiya 645.

 

[Sanug]

Check the film window with the empty camera without lens and hold it towards a white wall. Check with shutter set to "B" first and you may see what is in the way. I guess it could be the mirror not completely going upwards.

 

[Axelwik]

A Pentacon 6 was my first medium format camera some 35 years ago that had similar problems. It was replaced by a few Mamiya cameras that worked well, then eventually Hasselblad.

 

[Sanug]

A Kiev 60 is a good alternative to the Pentacon Six if you want to go with the excellent Zeiss Jena lenses.