Dust & Darkness (Mamiya 645 1000s)

[acphoto]

I just got back my first roll from my "new" Mamiya 645 1000s. I have two questions now...

1. There is a large squiggle of dust on every single frame, in the exact same spot. I've investigated every part of the camera with magnification and don't see any noticeable dust. or fuzzies. Where in the camera would dust be that would be consistently on every frame?

2. Several of my images are dark on one side - the top of my landscape shots, on the side for the portrait shots. It's a gradient darkness and always on photos shot at either 500 or 1000 shutter speed, but other photos at the same shutter do not have the dark side. What would cause one-sided darkness?

I greatly appreciate your input. This is my first run with medium format fun! ​

 

[tkamiya]

Welcome to APUG.

Does the dust/squiggle remain EXACTLY at the same spot and in exactly the same shape and orientation? Is it sharply defined? About where in the frame is it? Middle or at the edge? Can you scan the image and post it?

Your camera has a focal plane shutter. You can think of it as a SLIT is moving across right in front of the film. I wonder if it is sticking or dragging at high speeds? If you open the back and remove the insert, then trigger the shutter, you should be able to see this. Is the orientation of the dark band same as the direction that this slit travels?

 

[MattKing]

Is the dust actually on the negative, or are you seeing it only on prints or scans?

If the latter, it isn't the camera.

 

[acphoto]

It is in the exact same spot, in the same orientation, and doesn't more or change. It looks like a question mark on every frame. Here is a frame showing location - to the left side about half and inch from the edge, and about an inch or so from the top. Also a close up of the squiggle.

I also attached an image showing the dark side that happens. I removed the insert and triggered the shutter, but I'm not sure what I'm watching for. Can you clarify that last part? (Sorry, newbie here.)

 

[MattKing]

Like the photo .

Can you see the "squiggle" actually on the negative or slide, or are you only seeing it on print or a computer screen?

If it is only visible on a print or a computer screen, it is dust in/on a scanner.

 

[acphoto]

It looks to be on the actual negatives. And on two rolls.

And thanks, I'm a film addict, but also a beach addict.

 

[polyglot]

These were processed and scanned by a lab, right? It looks like there is a hair on the lab's scanner glass. Given that it's white on a scan from neg, we know the hair is recorded post-exposure (if it was blocking light pre-exposure, it would appear as black in the final image). So I don't reckon there's hair in the camera unless it's magical glowing hair or something.

That darkness in the upper-right corner looks like you used a polariser, which can cause unevenness in skies. It could also be uneven shutter curtain speed (the building looks a little darkened too...), e.g. if the first curtain opens a little slowly in one direction, you will get darkness on that side. If the shutter speed is uneven, try looking through the shutter at flashed white surface. If the shutter slit at high speed is narrower on one side than the other, then there's your problem. It will be very difficult to setup a test where you can directly observe this though.

If you don't mind burning a little film (2 frames!), and assuming the shutter is the typical reversing kind (moves one direction then the other on alternating frames), there is a simple test that has a chance of working. Point a flash and the camera at a white wall and take two consecutive photos at 1/1000. The flash should appear as a stripe across the frame (you are way above x-sync here) and on consecutive photos, it should appear on opposite sides of the frame. If the flash stripes are recorded as different widths, you know it's a shutter-unevenness problem.

Before you do that though: are the darkened frames all odd-numbered or all even-numbered? If not, then you may have some other problem.

 

[MattKing]

Are the negatives sleeved?

If so, do you still see something when you remove the negatives from the sleeves?

Can you see evidence of there being something physical on the negatives themselves, or is it an image of something visible in the negative?

 

[acphoto]

Interesting... they were scanned by a lab, and they are all definitely white, so I will assume it is something with the lab scanner. Definitely no fur growing on my camera. It's super clean, thus my surprise at the marks.

As for the darkness, I didn't use a polarizer or any type of filter. They were all shot with the 80mm 2.8 Mamiya lens. I don't think it's an even/odd frame thing either. One entire roll has very dark halves of photos. I might need to try the flash test, I suppose.

 

[polyglot]

Are the dark halves on alternate sides? Do they only occur at high speeds or at all speeds?

 

[Trask]

"...assuming the shutter is the typical reversing kind (moves one direction then the other on alternating frames)..."

Polyglot: a reversing focal plane shutter? I don't believe I've ever seen one. All FP shutters I've dealt with over the past 40 years have opened in only one direction. Open the back on a Leica M, set to 1 second and fire -- you'll see a curtain release (left to right IIRC), then the second shutter release to end the exposure. Advancing the film and cocking the shutter returns both curtains (now closed) to the left side, and it begins again. I've never seen an FP shutter where the two blinds alternate from side to side -- how would you tension the shutter?

I'm just trying to learn something new...

 

[polyglot]

Admittedly I've only looked at modern (electronic) AF 35mm cameras, but they all go in alternating directions. Shutter is closed with both curtains at one side (actually, top or bottom) of the frame and an exposure is made by moving one curtain then the other, leaving the shutter again closed by with the curtains on the opposite side. It then does the opposite for the next frame.

I've little idea how it works mechanically but see no good reason for it not to be symmetric - there would merely be two tensioning mechanisms and they are activated alternately when winding on.

 

[acphoto]

All at high speeds - but I haven't shot it much at low speeds. Always the same side. I noticed that it is much darker on one roll of film than the other, and the dark roll of film gave me some trouble with winding. I loaded it just like I loaded the first roll, and it started off rather tight. By the time I was halfway into the roll, it was very tight to wind. Would that have caused the darkness somehow? I'm not sure what I did that made it so difficult to wind - the first was fine, the second super tight, and now I have a third in it that is winding fine (like the first).

 

[polyglot]

The winding issue shouldn't cause uneven lighting across the frame. You can expose film mechanically by stressing it severely (e.g folding) but that wouldn't cause what you've shown above.

It's entirely possible the shutter in those is like Trask describes and not what I was thinking off, which would mean you get no alternation of darkness from side-to-side in the case of a lazy shutter. Another experiment you can do is to shoot a correctly exposed blank wall at the three highest speeds. If the darkening gets progressively worse at highest speeds, you can be confident it's the shutter.

 

[snederhiser]

Hello;
I have a 1000s and shoot b & w thru it. I have never had a roll run tight thru it and if I did, the dark bag would come out and unload the camera. Just taking a guess here but thinking the backing paper was wedged or torn causing the film to ride up against the focal plane shutter causing scratches and slowing the curtain explaining uneven exposure. Next time unload the camera and investigate the cause before running the roll thru, Steven.

 

[John Koehrer]

Admittedly I've only looked at modern (electronic) AF 35mm cameras, but they all go in alternating directions. Shutter is closed with both curtains at one side (actually, top or bottom) of the frame and an exposure is made by moving one curtain then the other, leaving the shutter again closed by with the curtains on the opposite side. It then does the opposite for the next frame.

I've little idea how it works mechanically but see no good reason for it not to be symmetric - there would merely be two tensioning mechanisms and they are activated alternately when winding on.

No AF or manual camera has alternate traveling shutter blades. It's downward from a cocked condition
Electronics control the shutter speeds, not the direction of travel of the blades.
Each set does have a slightly different appearance but only travel in one direction.

 

[Ric Trexell]

Use a piece of cardboard.

To see if the shutter curtain is hanging up, take a piece of cardboard like from a cereal box and block off a 1mm strip of the opening on one side of where the film goes. Then do the white test the others are talking about. You should see light when the shutter is released. Then try it a little further across but you will have to either use two pieces of cardboard or cut a slit (1mm) in the one you used. Then try that at the other end of the opening. In other words, try blocking off all of it except the left side, the middle and the right side. If you are seeing light at the 500 and 1000 speed then it is not the camera. If it is, that could mean it is time for a cleaning of the camera. Ric.

 

[John Koehrer]

Should have mentioned this earlier.
A graduated edge is a typical indication of curtain tension being out of balance.
On a K1000 the curtain speed(not shutter speed) is 12.5ms. each curtain is individually adjustable and should be close in value
~12.3-12.7ms
The curtain speeds not agreeing will give this type of result and the effect is greater at higher shutter speeds.

 

[acphoto]

Thank you all for these intelligent replies. I actually discovered that I purchased it with a warranty, so I sent it back for repair/replacement. Here's hoping the next one has a well-behaved shutter.