problem with increased edge density with contax 645

GraemeMitchell · Dec 6, 2008

I'd had this happen before on a job and actually wrote it off as bad processing, but it just happened again. Both times it was with a Contax 645, 220 film. Each time it was with a different camera (I rent, and the rentals were from different places.) It's the only two times I've used this camera. So, I'm concluding it's the camera...at this point...

In the attached example you'll notice the right side of the frame has increase density gradient. Oddly, so does the bottom of the frame, though more slight and barely noticeable in the attached jpegs size. Now, my thought that it could be the shutter seemed to make sense, except for it taking places on 2 of the 4 sides of the frame. The gradient isn't only density, but also has a slight green color cast. Which then makes me think maybe the film isn't flat? Or some user error?

Never seen it with other cameras. Wanted to get feedback to see if it's a known thing, and if there's anything I'm doing wrong that can be corrected. Making the same mistake twice is painful enough!

2F/2F · Dec 6, 2008

I can't see the problem in the pic.

GraemeMitchell · Dec 6, 2008

Huh, don't notice the right and bottom edges are darker...? Let me up the contrast and crop in so it's easier to see. it's apparent at bigger sizes...and if you look at the film carefully, there too.

aparat · Dec 6, 2008

Did you set the pressure plate for 220?

GraemeMitchell · Dec 6, 2008

Yes. And there were a number of backs being used. The film from all of them had this issue.

2F/2F · Dec 6, 2008

I see it in the second pic. It looks just like a film flatness issue. Not sure of the specifics of that camera. maybe there is some part that holds the pressure plate firmly against the gate that wears out over time. However, that would make the edges lighter, not darker, so perhaps it is being pushed forward too much so that the film bows into the gate a bit.

GraemeMitchell · Dec 6, 2008

All the Contax 645 stuff in the rental houses is by this point old and has seen lots and lots of use. Lots. So maybe it's an issue of worn backs...

MikeSeb · Dec 7, 2008

I don't recall seeing this in my Contax 645 film backs. I've only used 120 film, however.

Ian Grant · Dec 7, 2008

I get a similar problem with one of my Mamiya 645's. In my case it's caused by a piece of fabric along the top edge of the mirror. This doesn't move ot of the way properly and just clips the edge of the image during exposure. Being a few mm away from the film plane it causes a very similar unsharp edge to your example.

Ian

GraemeMitchell · Dec 7, 2008

Ian, thanks, something like that makes much more sense, since it's such a consistent problem across different backs. I'll look for it next time I use the camera.

Ian Grant · Dec 7, 2008

Graeme, the official UK Mamiya repairers have failed to fix the problem on my camera twice, so I'd expect a rental department might not spot a similar problem

Ian

JHannon · Dec 7, 2008

I have a Mamiya M645 that will do this at certain shutter speeds. In my case, I found that the shutter curtain would lag a bit toward the last of it's travel. It would sometimes not fully seat or retract but stay in the frame a bit.
I never did get to fix it. The Mamiya people refer to it as curtain bounce.

John Koehrer · Dec 7, 2008

Shutter bounce sounds right. Which way does the film travel? Do you recall? Whichever it is, the bounce has to be on the side of the closing(2nd) curtain.

2F/2F · Dec 7, 2008

It doesn't look like a classic case of shutter bounce to me. The gradation with shutter bounce looks different, and if it was shutter bounce, it would only occur on one edge of the film, not both the side and the bottom, and it would also occur regardless of film format. Shutter bounce usually produces a more clearly defined line as well. What I think is happening it that, for whatever reason, those two edges are farther from the lens. Perhaps the back is simply not as tightly connected to the body as it should be due to age, use, being beat on by various renters, lack of service, etc. It could also be that the gears for the take up reel are out of spec. or worn, and are not pulling the film tightly enough to keep it from bowing into the film gate. It could be that the film is not being pulled perfectly straightly from one spool to the next, resulting in a skewing of the film, which releases its pressure by pushing the film into the gate. It could be that the pressure plate is out of position laterally, or was not properly seated when flipped to the 220 side. I really just think this is an issue of worn out backs, or possibly improperly-loaded backs. If this is the problem, I would expect that on careful inspection, the image is not TACK sharp as well; at least not over the entire surface area.

JHannon · Dec 7, 2008

John Koehrer said:
Shutter bounce sounds right. Which way does the film travel? Do you recall? Whichever it is, the bounce has to be on the side of the closing(2nd) curtain.

In my case if I shot horizontal it would appear on the bottom of the frame. If I held for a vertical like the OP, It would appear on the right. Since the sky is at the top, it would not be as noticable in a horizontal shot.

GraemeMitchell · Dec 7, 2008

JHannon said:
In my case if I shot horizontal it would appear on the bottom of the frame. If I held for a vertical like the OP, It would appear on the right. Since the sky is at the top, it would not be as noticable in a horizontal shot.

That's consistent w/ the horizontals I took.

The film's sharp corner to corner, even within the increased density, which kind of rules out film flatness.

I just looked and the 120 B&W displayed the same issue, so it's not a 120 vs 220 issue

Given the # of backs and the amount of film shot, 2 people loading through the day, and all the other redundancies, I'm going to go with a shutter issue. Just surprising I've had it on both the bodies I used...

Well, kind of a pita to fix it well in the print, but not impossible.

Thanks for the ideas guys.

John Koehrer · Dec 8, 2008

The shutter curtain wouldn't have to bounce all the way into the film aperture to fog as slightly as that one but it should show on the space between images also.
The next time you rent a body check for bounce visually, fire the camera while holding it up to a relatively bright light source.

TerencePatrick · Dec 14, 2008

Hey Graeme, were you shooting with strobe? The Contax can sometimes be inaccurate with its flash sync. Setting it to 1/60th will usually fix it.

Tom Duffy · Dec 14, 2008

GraemeMitchell said:
I'd had this happen before on a job and actually wrote it off as bad processing, but it just happened again. Both times it was with a Contax 645, 220 film. Each time it was with a different camera (I rent, and the rentals were from different places.) It's the only two times I've used this camera. So, I'm concluding it's the camera...at this point...

In the attached example you'll notice the right side of the frame has increase density gradient. Oddly, so does the bottom of the frame, though more slight and barely noticeable in the attached jpegs size. Now, my thought that it could be the shutter seemed to make sense, except for it taking places on 2 of the 4 sides of the frame. The gradient isn't only density, but also has a slight green color cast. Which then makes me think maybe the film isn't flat? Or some user error?

Never seen it with other cameras. Wanted to get feedback to see if it's a known thing, and if there's anything I'm doing wrong that can be corrected. Making the same mistake twice is painful enough!

I don't see that you mention whether this is slide or negative film. Based on the appearance of the thumbnail, if negative film, it looks like the shutter needs adjustment. I had the same thing happen to mine, more pronounced actually, after just less than three years of use. I bought mine almost on the first day they hit the stores and always thought the problems was due to it being one of the first ones assembled. I sent the camera back to Contax in 2000. Don't know exactly what they did, but it hasn't had a problem since.

Take care,
Tom

elekm · Dec 14, 2008

Getting it serviced might be a bit problematic, as Kyocera exited the camera business several years ago.

However, ToCad appears to be handling warranty and non-warranty service for Contax gear (http://www.tocad.com/service.html).

GraemeMitchell · Dec 14, 2008

TerencePatrick said:
Hey Graeme, were you shooting with strobe? The Contax can sometimes be inaccurate with its flash sync. Setting it to 1/60th will usually fix it.

Indeed, was shooting with strobes the whole day, at 125th. That's be interesting if that was the prob.

TerencePatrick · Dec 14, 2008

GraemeMitchell said:
Indeed, was shooting with strobes the whole day, at 125th. That's be interesting if that was the prob.

It also helps if using strobes with short flash duration. If you're blasting a set with multiple packs and heads, I'd go down to 1/60th.

problem with increased edge density with contax 645

GraemeMitchell

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problem with increased edge density with contax 645

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