Illumination pattern along the long side of a frame (in bright light)

[f8low]

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I noticed a single negative from my M2 that shows a strange bar-like illumination pattern on the long side of the frame. I have not noticed this before or in the ten-ish rolls I shot afterwards. The shot must have been taken with 1/500 or 1/1000 and fairly closed aperture (with a Summaron 35mm 2.8). Curiously there seems to be another pattern in the top left corner that runs slightly diagonally. Attaching a version with pronounced contrast in the relevant region.

Question: Does this stem from the harsh light (i.e. internal reflections etc) or from a shutter problem? It's not a scanning artefact, it does show on the negative.

I am not super familiar with how the shutter in an M2 works but I would have expected a problem there to show in the orthogonal direction. On top, I am fairly sure I shoot 1/500 and 1/1000 frequently so it should have appeared more often?
 

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Edited September 29, 2023 by f8low

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[dpitt]

Yes the shutter works more in horizontal direction. This looks more like a small light leak to me. Maybe the back door/bottom that is leaking light? In that case you could test with some black tape on the outside to seal it off. And then shoot a test roll.

 

[Tom R]

Is there evidence of light-banding in the rebate area---for example, do we see dark bands running down to the sprocket holes on the frame(s) in question?

Is this frame at the beginning or the end of the roll?

I'm no technician but I'm betting that at least a few might be reading this thread.

[250swb]

If the band is darker on the print than the rest of the photo that must mean the band is less dense on the negative, no? Light leaks tend to be lighter in the print because they are denser on the negative, don't they? So maybe a shadow cast by the shutter gate that's exaggerated by the direction of the light?

[f8low]

@250swb agree, a light leak should produce a negative that is more dense, but this band isn't. At least not in all areas. 

@Tom R you might be onto something there. It is the first shot of the roll and the first on this strip of six. And yes, the edges are slightly darkened.

Attaching a non-inverted picture of the negative - one exposed for the picture, one for the carrier. To the left, the roll strip ends. To the right you see the next picture. Interestingly there is a slightly darkened area also on top of the first shot and between the first two shots. I do not see this between the other shots.

PS: Arguably, the negative is a bit overexposed, i.e. too dense as a whole.
 

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Edited September 29, 2023 by f8low

[jerzy]

this is outside of the frame but might have the same origin  - if you can exclude developmengt problem this and your intial problem may be caused by light seal on backdoor - in upper part. If however theseshown defects are from development than your initial problem could be be caused by deffective light seals in the baffle (in front of the shutter curtains)

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[f8low]

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29 minutes ago, jerzy said:

this is outside of the frame but might have the same origin  - if you can exclude developmengt problem this and your intial problem may be caused by light seal on backdoor - in upper part. If however theseshown defects are from development than your initial problem could be be caused by deffective light seals in the baffle (in front of the shutter curtains)

 

This pattern is indeed visible across the whole roll in different intensities (sometimes it's missing). The roll was developed by yours truly so mistakes could certainly have happened. Though my gut feeling is that what we see outside the frame is not the same that we saw on the first frame. To me the small black specks seem development related while the illuminated bar seems exposure related.

(iPhone shot attached)

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Edited September 29, 2023 by f8low

[adan]

You are getting a flare patch from stray sunlight hitting the inside of the camera (overall bright area) outside of the image area.

But the set-back of the film (or sensor - either one) behind the shutter shades the edge of the image area for a couple of mm, producing the relatively dark band (which is actually simply normal exposure, minus the flare light).

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[f8low]

28 minutes ago, adan said:

You are getting a flare patch from stray sunlight hitting the inside of the camera (overall bright area) outside of the image area.

But the set-back of the film (or sensor - either one) behind the shutter shades the edge of the image area for a couple of mm, producing the relatively dark band (which is actually simply normal exposure, minus the flare light).

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That's super interesting, thanks for the explanation and the nice drawing. The geometry of this makes a lot of sense to me. Clearly there was a hell lot of light inside the camera - the scene was bright and I overexposed a bit.

I have one follow up question though. Are such rays of light that hit the bottom of the camera also present in every 'well behaved' scene or are they so to speak 'stray light' that stems from reflections inside the lens? To put it differently, is this light that left the 'intended' path through the camera? If that's the case, the choice of lens (and me not using the hood) would amplify the situation. The Summaron definitely does not have the most modern coating...

Edited September 29, 2023 by f8low

[BernardC]

1 hour ago, f8low said:

Are such rays of light that hit the bottom of the camera also present in every 'well behaved' scene or are they so to speak 'stray light' that stems from reflections inside the lens? To put it differently, is this light that left the 'intended' path through the camera? If that's the case, the choice of lens (and me not using the hood) would amplify the situation.

The lens projects a circular image, so some of that lands outside of the film area and can be reflected back to the film. A lens hood should help. You may also have a reflective surface inside the camera. Those can sometimes be touched-up with black paint.

[f8low]

19 minutes ago, BernardC said:

The lens projects a circular image

Again, that makes a lot of sense 🤣 Thanks for your explanation, too!

[adan]

A follow-up diagram in support of BernardC.

(The questions you are asking come up fairly often, so I've saved these informational graphics for re-use.  )

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Ideally, one would use a lens hood that crops the scene in front of the lens to a rectangle the same shape as the film area. Thus minimizing such reflection-flare.

Hollywood and cinematographers use those - but they are quite bulky for carry-around cameras.

https://www.bhphotovideo.com/c/product/1346398-REG/cambo_99050324_compendium_and_lenshood_for.html/?ap=y&ap=y&smp=y&smp=y&smpm=ba_f2_lar&lsft=BI%3A6879&gclid=EAIaIQobChMI46fh9YvUgQMVVQx9Ch2fuQB3EAQYAiABEgI3u_D_BwE

Leica has provided smaller rectangular hoods for some lenses, over the decades (including today). Not sure whether one exists for the 35 Summaron.

https://wiki.l-camera-forum.com/leica-wiki.en/index.php/SOOBK

https://wiki.l-camera-forum.com/leica-wiki.en/index.php/XIOOM

https://wiki.l-camera-forum.com/leica-wiki.en/index.php/12459

Edited October 1, 2023 by adan

[hansvons]

1 hour ago, adan said:

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Ideally, one would use a lens hood that crops the scene in front of the lens to a rectangle the same shape as the film area. Thus minimizing such reflection-flare.

Hollywood and cinematographers use those - but they are quite bulky for carry-around cameras.

They can create rectangular bokeh balls. Not nice. 

[Steve Ricoh]

On 9/29/2023 at 9:13 AM, f8low said:

I noticed a single negative from my M2 that shows a strange bar-like illumination pattern on the long side of the frame. I have not noticed this before or in the ten-ish rolls I shot afterwards. The shot must have been taken with 1/500 or 1/1000 and fairly closed aperture (with a Summaron 35mm 2.8). Curiously there seems to be another pattern in the top left corner that runs slightly diagonally. Attaching a version with pronounced contrast in the relevant region.

Question: Does this stem from the harsh light (i.e. internal reflections etc) or from a shutter problem? It's not a scanning artefact, it does show on the negative.

I am not super familiar with how the shutter in an M2 works but I would have expected a problem there to show in the orthogonal direction. On top, I am fairly sure I shoot 1/500 and 1/1000 frequently so it should have appeared more often?
 

Welcome, dear visitor! As registered member you'd see an image here…

Simply register for free here – We are always happy to welcome new members!

 

I like the effect but don’t want to deliberately damage one of my cameras, otherwise I’d be in for some of this. When I first got my hands on my Pen FT with 1:1.4/40mm there was no lens hood and it made some lovely flaring that somehow affected adjacent frame. I purchased a lens hood and the effect vanished. Guess what I’m going to do on my next outing in bright light.