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jbl

distance between frames

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I've been shooting a lot of B&W film in my MP that I've then been processing myself and scanning in a Nikon Coolscan 5000 scanner using the bulk film feeder. I scan about 18 frames at a time because that's what fits in the scanner without the end dragging on the floor at the beginning of the roll :-).

 

I scan in Vuescan with autocropping off and I've noticed that sometimes the scanned frame is misaligned to the left, rather than being centered in the scanned frame, it's close to the left side, in some cases even the next frame is visible a bit on the right-side of the scanned image.

 

I looked at the film itself and noticed that the space between successive frames seems to vary occasionally: usually it's a consistent amount of space, but every so often (a few frames a roll) the start of a frame bleeds into the gap between frames.

 

Has anyone ever seen this before? The only thing that I can think of is that maybe I'm not fully winding the film or something, but I'm at a loss.

 

-jbl

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Backward tension not even, perhaps? The new MPs, with their high friction rewinds, should help prevent this, if you take up the slack when loading.

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As far as I know, I have the slack taken up when I load, though I'm not sure I know exactly how far I'm supposed to go :-).

 

-jbl

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I normally take up the slack once the bottom cover is on. That way I can tell if the film is firmly in the take-up spool because there's resistance and once I start winding the first two waste shots the knob turns. As for how much, I normally rewind until the slack is gone, no more. I don't like the feeling of film on film under friction. The MPs knob should stop the slack from returning, but I'm not actually sure if this could be the cause of your problem. It's just a possibility.

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The distance between frames depends on the focal length of the taking lens. A 90/135 mm at closest distance is "further" from the film than a 21 mm lens at infinity. Therefore the angles of coverage at the film plane actually differ. The WA lens's image can sneak closer to the frame edge than can the longer lens.

If you are sceptical, take a couple with the longest lens you have, then a couple with the shortest focal length. The horizontal frame size will be greater by a speck or two than the longer lens shots.

 

John.

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It depends who serviced the thing. Properly serviced MP the spacing will be generous and even. When it is not going well, the wind on transport varies a bit and you get a good variation.

Solms can even make your film transport diagonally across the film gate, or have the sprocket holes transport across the film gate, effectively leaving you with a crop format 35 on one side, and an image in the sprocket holes on the other. Wonderful they are.

If it is bad enough and bugs you a competent clean and adjust should even things out again.

What you are seeing is not your fault, and while you should be pre tensioning anyway, it wont fix or mitigate the effect.

Edited by rob_x2004

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"It depends who serviced the thing. Properly serviced MP the spacing will be generous and even. When it is not going well, the wind on transport varies a bit and you get a good variation".

 

With due respects, that is what a polite Spanish workmate used to describe as "toros escrementos"

Unless Solms has some genius who either has found a way around the laws of geometry, or have installed a couple of little electronic men to move the vertical frames to and fro, see the extract from a respected Leitz spokesman on the jpeg attached.

 

John.

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If the distance between the centers of the frames varies, then your camera winds unevenly. If the width of the frames (and, hence, the width of the gaps) varies, the more likely cause is your using lenses of different focal lengths.

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1) "Toros excrementos" or not - it is perfectly possible for the mechanism to get loose and sloppy. I would NOT expect it in an MP (too recent a camera) but my original M4-2 at age 25 had rather - random - frame spacing at times. The toothed sprocket shaft had some play.

 

2) The variation in frame size due to focal length is pretty small these days. Back in the era of the Zeiss Hologon and the Super-Angulon wides, which practically touched the shutter, there was indeed a noticeable difference - those wide lenses shoot light under the film gate at an angle to expose a larger area (sometimes all the way to the film sprocket holes). But with the "meterable" retrofocus lenses made since 1980 I've never seen a difference in image size on film.

 

But certainly try the test John mentions and see for yourself.

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The distance between frames depends on the focal length of the taking lens. A 90/135 mm at closest distance is "further" from the film than a 21 mm lens at infinity. Therefore the angles of coverage at the film plane actually differ. The WA lens's image can sneak closer to the frame edge than can the longer lens.

If you are sceptical, take a couple with the longest lens you have, then a couple with the shortest focal length. The horizontal frame size will be greater by a speck or two than the longer lens shots.

 

John.

 

 

...not sure I agree with you, John - the image area of a Leica M camera (not the lens) is constant and not dependent on the focal length of the lens in use. Any variance in the space between the frames is therefore a product of the force or mechanism that transports the film, or the film itself. IMHO.

Edited by aesop

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John,

Lens coverage is circular. The masks in the body make the format and the changes between the masks the lens angle over the short distance mask to film plane can only make so much difference.

And I am sorry guys, my new out of box MP got stalked by solms and I have plenty of experience with variation in frame spacing. It results from sloppy adjusting on the wind on I should suspect. My camera went from 1 to 4 mm spacing to near precise even spacing with a smooth wind on courtesy of the Aus distributers work chasing a light leak resulting from poor initial assembly, then it went from 1 to 3plus and a diagonal film transport post solms repair with a host of other problems, then a 2 to 3 spacing with a cropped image but straight after a second repair with a host of other problems.

You are wrong, badly irregular frame spacing can be improved to perfectly acceptable with proper service.

Regards.

Edited by rob_x2004

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the start of a frame bleeds into the gap between frames.

 

You may need to send the camera with a sample cassette set of negatives to your repair person if the camera is used for critical unrepeatable work. Lube gumming or mechanical problems can upset the regular spacing of frames, it should be regular.

 

As previous posters have said the negative size will not necessarily be constant, as you swap lenses, if you have any of the '70 Leitz non reversed telephoto wides, or a FSU J12, or long focus lenses. But they should be at a fixed spacing allowing for any size variability.

 

Your expression 'bleeds into the gap', does it just mean one frame is offset, relative to the others?

 

Noel

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".....the image area of a Leica M camera (not the lens) is constant and not dependent on the focal length of the lens in use."

 

Sorry, you may not be aware that this happens with older Leica M super-wides, but it is a real effect. However, I agree that mechanical slop is a more likely suspect, unless the OP confesses to shooting with a Super-Angulon and 135 interchangeably.

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I think I was using a Noctilux for the whole roll where I noticed this. I have two MP bodies and have been going through my negatives to figure out if it both exhibit this or not. So far, it's inconclusive, so I'll keep monitoring it to see if one of the bodies has the problem or not.

 

It sounds like the issue is mechanical though and not optical.

-jbl

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I just ran a test with both MP bodies and they both exhibit the issue. How likely is it that they're both off?

 

-jbl

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".....the image area of a Leica M camera (not the lens) is constant and not dependent on the focal length of the lens in use."

 

Sorry, you may not be aware that this happens with older Leica M super-wides, but it is a real effect. However, I agree that mechanical slop is a more likely suspect, unless the OP confesses to shooting with a Super-Angulon and 135 interchangeably.

 

 

...let me understand this, Andy - according to your diagram, extraneous light from the "long lens" does not spill under the gate to fill the frame, right?

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Mm, yes - I haven't even seen any M camera/lenses since I sold my M4 20 years ago, so forgot about the retrofocus design of later WA lenses.

If one has two, say 21mm lenses, one of which is of 1960s vintage, the other a retrofocus newer one; and both are of precisely the same focal length; and each focussed exactly on infinity; and the newer one covers the same negative area horizontally as a long lens, the older lens (because its horizontal image takes up more space on the negative) is therefore covering a greater horizontal angle of view.on the film. That is regardless that each lens covers the same image circle.

 

Back to the asylum, John.

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I've been shooting a lot of B&W film in my MP that I've then been processing myself and scanning in a Nikon Coolscan 5000 scanner using the bulk film feeder. I scan about 18 frames at a time because that's what fits in the scanner without the end dragging on the floor at the beginning of the roll :-).

 

I scan in Vuescan with autocropping off and I've noticed that sometimes the scanned frame is misaligned to the left, rather than being centered in the scanned frame, it's close to the left side, in some cases even the next frame is visible a bit on the right-side of the scanned image.

 

 

-jbl

 

If I understand what you are saying, It's not the camera, but the Vuescan software that is causing the problem

 

I used the same set-up for a time and found that Vuescan mis-aligned the frames when using the bulk film loader. It started out fine, but would run into the next frame after a time.

Silverfast did the same thing, but had an adjustment tool.

Nikon scan was the only software that would accurately frame the image for each shot on a roll.

It got frustrating, but I ended up using Nikon Scan for the full roll scans and Vuescan for 6 or under strips or slides.

Edited by lewis44

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aesop - correct.

 

The film rails (vertical black bars between the film and the shutter in the diagram) hold the film slightly away from the shutter opening. Creating an overhang like an awning over a sidewalk. At high noon (long lens) the awning provides shade. In the late afternoon or early morning, the low angle sun (old-style superwide lens) can shine in under the awning and hit the sidewalk.

 

Doesn't happen with SLR lenses since even a very wide SLR lens is still 40+mm away from the shutter and film (to make room for the swinging mirror). Doesn't happen as visibly with Leica's post 1980 wideangles (designed to sit further from the film, like SLR lenses, to allow metering). Doesn't show up with digital since the sensor has its own masked image area and doesn't depend on the shutter opening to define the image edges.

 

If there were no film rails and the film sat tight against the shutter opening (like lowering that awning until it actually sat on the sidewalk) - then all lenses would produce exactly identical images regardless of optical design and distance. No gap for "spill".

 

lewis44 - jbl does mention "I looked at the film itself and noticed that the space between successive frames seems to vary occasionally. "

 

So it isn't just the automatic frame sensing of the scanning software in his case - although I agree with you that that can be not very good and cause similar problems of partial images.

Edited by adan

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aesop - correct.

 

The film rails (vertical black bars between the film and the shutter in the diagram) hold the film slightly away from the shutter opening. Creating an overhang like an awning over a sidewalk. At high noon (long lens) the awning provides shade. In the late afternoon or early morning, the low angle sun (old-style superwide lens) can shine in under the awning and hit the sidewalk.

 

Doesn't happen with SLR lenses since even a very wide SLR lens is still 40+mm away from the shutter and film (to make room for the swinging mirror). Doesn't happen as visibly with Leica's post 1980 wideangles (designed to sit further from the film, like SLR lenses, to allow metering). Doesn't show up with digital since the sensor has its own masked image area and doesn't depend on the shutter opening to define the image edges.

 

If there were no film rails and the film sat tight against the shutter opening (like lowering that awning until it actually sat on the sidewalk) - then all lenses would produce exactly identical images regardless of optical design and distance. No gap for "spill".

 

lewis44 - jbl does mention "I looked at the film itself and noticed that the space between successive frames seems to vary occasionally. "

 

So it isn't just the automatic frame sensing of the scanning software in his case - although I agree with you that that can be not very good and cause similar problems of partial images.

 

 

...gotcha, Andy - makes sense. I was labouring under the error that the film sat flush against the shutter opening. Thanks.

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