Grandient on M2 photos

[MikeRZ67]

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Hi,

I noticed a strange issue on my M2 with the C-Biogon 35: Some pictures (especially in strong sunlight, but that could be a coincidence) show something that looks like an exposure gradient from left to right. See the attached photo. I just had the M2 CLA'ed a year ago, so I hope it's not the camera... Any ideas? Could it be the lens?

Thanks,
Michael
 

Edit:

One theory I had was that it could be the light source I use for DSLR-scanning my photos. But when I take a photo of the light source only it doesn't show that light distribution. So, probably something else.

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Edited June 12, 2021 by MikeRZ67

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[jaapv]

Looks like a shutter issue. The camera needs attention. Welcome to the forum

[250swb]

The colour cast exaggerates the effect you are talking about. Before sending your camera for another service try scanning the negative again but the opposite way up from the last orientation just to check if the lighting is even. And what light source are you using, not an iPad I hope.

Edited June 12, 2021 by 250swb

[MikeRZ67]

2 hours ago, jaapv said:

Looks like a shutter issue. The camera needs attention. Welcome to the forum

Thank you!

Ah, that's unfortunate... I just remembered that the M2 had a similar issue when I first got it: One side would be underexposed while the other one would be overexposed. That's why I had it CLA'ed in the first place. It was fine for a while, but apparently now, a year later, it's de-calibrating itself again. Not sure if that means that there is something wrong with the camera or the place where I had it serviced (Leica Store in Copenhagen)...

35 minutes ago, 250swb said:

The colour cast exaggerates the effect you are talking about. Before sending your camera for another service try scanning the negative again but the opposite way up from the last orientation just to check if the lighting is even. And what light source are you using, not an iPad I hope.

That's a good idea. I'll try that. I'm using a Skier Copy Box and a Sony A7R3 on a Novoflex MagicStudio Repro Column. Although I haven't figured out what makes it 'magic' so far, I've been happy with the results I've been getting with that setup.

[TomB_tx]

Not all CLAs are equal. Most careful is a full stripdown to clean off all traces of old lubes before assembling with new lubes, and Leica specified 7 or more different lubes depending on the area of the camera. Of course, that's also the most expensive method.

Some "CLA" don't do much "C" and just add lighter oils to free things up. Then with age the old lube residue migrates and the problems return...

[Andy_Shields]

I'll second a proper repair of your shutter capping issue. It's easy to increase the spring tension and power through the aging lube but that solution is a bandaid. 

[adan]

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On 6/12/2021 at 1:08 AM, MikeRZ67 said:

Some pictures (especially in strong sunlight, but that could be a coincidence) show something that looks like an exposure gradient from left to right

Not coincidence.

In stronger light, you naturally use a faster shutter speed. Which with the focal-plane shutter of the Leica cameras, means a narrower and narrow physical gap between the two shutter curtains.

For example, at 1/50th second (sync speed, lightning-bolt shutter dial marking), the gap is the entire width of the picture (~36mm) - the second curtain starts to move as the first curtain has reached the far side of the frame.

At 1/1000th second - to let in 1/20th as much light - the moving gap is only ~1.8mm wide.

If the sticky curtain is delayed in accelerating (or decelerating) by 1mm as it crosses the frame, it will result in a ~1-stop (half the light) exposure reduction (fade-in or fade-out) at 1/1000th sec.

1/2 the fade-in or fade-out at 1/500th

1/4 the fade-in or fade out at 1/250th

1/8th the fade-in or fade out at 1/125th (probably already too little to be noticeable)

1/16th as much fade at 1/60th

1/20th as much fade at 1/50th

....etc.

[MikeRZ67]

22 hours ago, adan said:

In stronger light, you naturally use a faster shutter speed. Which with the focal-plane shutter of the Leica cameras, means a narrower and narrow physical gap between the two shutter curtains.

Thank you for the explanation! That really sounds like it is the shutter causing this.

Well, the M2 is on its way to another CLA at a different place now. And hopefully this time they will focus a bit more on the "Cleaning" part.

 

[tommonego@gmail.com]

Yes, it needs a shutter job, at what level the technician should tell you. My 1957 M3 needed a curtain replaced with a similar issue. Want you need is a LA lube and adjust, maybe more. Send along the image with the camera.

[nitroplait]

20 hours ago, MikeRZ67 said:

Thank you for the explanation! That really sounds like it is the shutter causing this.

Well, the M2 is on its way to another CLA at a different place now. And hopefully this time they will focus a bit more on the "Cleaning" part.

 

If only a year ago, you should try to exercise your statutory right of complaint, which is 2 years in Denmark (and elsewhere in EU if I am not mistaken).