Pentax 6x7 Problem (see photos)

[PatrickT]

Hi Guys, problem for you! Yay!

My Dad recently got a lens for his Pentax 6x7 after having it sit on his desk for about 3 years. He shot a test roll through it and after having it processed with prints, discovered something weird. A few of the photos looked fine, a few were overexposed (possible user error) but several of them had some sort of "haze" on part or all of the image. See photos below...goes from good to BAD...all from the same roll of film.

(these are crappy scans from the prints, although the problems are evident in the negatives as well).

Does anyone have any idea what this could be? Three or so years ago, the camera worked fine...gorgeous images. Obviously, there was no obstruction in front of the lens or anything like that (we could have figured that out ourselves 🙂 ).

Any thoughts? We're stumped.

 

[ItsReallyDarren]

The haze looks inconsistent from each of the pictures. I was going to say the shutter spacing is off but the dark areas are curved.

Take a look at the lens, maybe the aperture blades are sticking. If the camera and lens sat for a while its possible the aperture blades start gumming up. Remove the lens, stop down all the way, and quickly press the aperture tab. If you see some of the blades are slow to return that could be the culprit.

 

[l-noir]

Hey PatrickT,

I've seen this same kind of behavior from my pentax 6x7. I noticed that all your pictures were taken on a bright, sunny day. Were you using the 1/1000 shutter speed?

I've found that, whether due to a dying battery (which would be surprising, as its fairly new) or dried up lubricants, the shutter curtains sometimes travel slightly out of sync. Not a lot, but enough that it can affect the exposure at the fastest shutter speed.

Try firing off a few exposures at 1/1000 with the back of the camera open (its tricky because you have to rotate the film counter with your thumb to a number higher than zero before opening the back or the shutter won't fire). Look into the back of the camera, and out through the lens as the shutter fires. You should be able to see some inconsistency in the brightness of the frame. sometimes brighter, sometimes dimmer, and sometimes you'll see almost nothing (provided your issue is the same as mine).

Unfortunately I haven't come up with a solution yet. Right now I'm just limiting myself to 1/500 or less which should alleviate the problem (but i can't confirm as a i haven't finished and developed the latest roll). Once i get the results back, i'll let you how they turned out.

I imagine the solution to my problem (and potentially your's) would be a CLA, but for the price you could probably pick up a 90's vintage ex+ condition 67, so its a tough choice.

 

[PatrickT]

Thanks for the response guys. I got an email from my Dad (he read the thread) and said that he did shoot the majority of the shots at 1/1000, except for the first one, which was later in the day (less light). He said that the battery used for these particular shots was old...and has since put a new one in.

This seems as if it could be the problem. He is going to try what you guys mentioned with the lens and the camera body (shutter) and see what happens. The lens he just got for it is directly from KEH (Ex condition) so I would hope that there is nothing wrong with it.

Thanks again and any other potential ideas are welcome!

 

[emraphoto]

could you find out which lens it is?

 

[emraphoto]

to add... i have a body that i love and it tends to get "sticky" if left to sit for too long. especially at 1/1000. i know a CLA is in order but if i work it a bit every while it seems to function fine.

 

[PatrickT]

The lens is the 55 f/4, recently purchased in "Ex" condition from KEH.

 

[titrisol]

Seems more like a shutter problem; maybe the new battery may solve it or maybe you need to send the body for a CLA

Check the lens against the light, and if it is clear (maybe some dust specks inside) it should be A-Ok