What are these spots & why do they show up?

[shirubadanieru]

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Hi everyone, every time I shoot backlit with old lenses (which flare) on any digital M, I always get these weird spots (?) on the flare. I always wonder why it happens and what they are...Can anyone enlighten me? Here are two examples that I shot today on the M10M with the Elmar 5cm. 

First I’ll share the actual shot without the spots after I removed on LR and then I’ll add two close ups of the spots before I removed them.

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Edited May 7, 2020 by shirubadanieru

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[shirubadanieru]

And here are two close ups with the spots or whatever I should call this

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[AndreasG]

Dust on the sensor?

[shirubadanieru]

10 minutes ago, AndreasG said:

Dust on the sensor?

Don’t think so as they only happen when it’s shot backlit and in no other circumstances (plus this happens with all digital Leicas I’ve tried it on) 

[Knipsknecht]

... dust inside or on the lens that is more or less visible depending on the angle of light??? It's just a guess, but these spotty things really look like some kind of dirt. Do they really bother you? I mean, even in the close ups they're hardly visible.

[shirubadanieru]

Not a bother & I can remove it on LR. I'm just curious as to why this happens & what it is and would like to learn from people here who might have any insights

Edited May 7, 2020 by shirubadanieru

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It does not look like dust, but it seems to be some specks on the sensor. I see no other explanation for them to be so sharp. 

Follow the usual routine for detecting dust on the sensor. Repeat with different lenses. If the spots remain the same, it's on (or in) the sensor.

The usual routine: point your camera at a featureless and homogenously lit plane. A spotless sky will do nicely, or a wall without any nails. De-focus the camera as much as it will let you: set it to 1m for the sky, to Infinity for your wall at 1m. For detecting dust, stop the lens down as much as possibly. For detecting other material on the sensor, it should not matter much. Set the exposure such that the featureless plane will yield a middle or bright grey. Repeat with the camera at different positions, so that the same part of the sky or wall will be on different places of the sensor in subsequent shots.

[frame-it]

looks like dust on the sensor...light that's diffracting back from the sensor makes the dust spots visible..

 

i think

[Guest]

Only explanation I see is particles close to the sensor (e.g. on the filters of the Bayermatrix). Thus they are reasonably sharp. Dust on the lens does not image sharp on the detector. It only reduces light throughput all over the scene and scatters light.

Hermann-Josef

[convexferret]

I've seen this before in other lenses. In backlit situations where the light reflects around inside the lens, dust on certain elements (may be the outside elements) is resolved sharply. Pure chance depending on the lens design. In the Canon 35 f2 LTM you get a perfectly sharp image of the aperture blades reflected on top of the image.

[Stealth3kpl]

It's 5G infectin the sensor

Pete

[Herr Barnack]

Ye gods, man!  Your sensor has been infected with the Coronavirus!!  😳

Edited May 7, 2020 by Herr Barnack

[davidmknoble]

@shirubadanieru

If you have a different lens, put it on the camera, stop down to f/11 or f/16 and set the exposure to A.  Shoot at a ceiling or white wall, but be sure it is way out of focus.  If you get the same spots, it is on the sensor.  if not, try the original lens the same way, if you get spots, it is something in the lens. 

The high f/stop puts everything into sharper focus (dust) and the white wall, slow exposure, out of focus lens, keeps anything but the dust out of focus.

 

[stefanusj]

On 5/15/2020 at 10:22 AM, davidmknoble said:

@shirubadanieru

If you have a different lens, put it on the camera, stop down to f/11 or f/16 and set the exposure to A.  Shoot at a ceiling or white wall, but be sure it is way out of focus.  If you get the same spots, it is on the sensor.  if not, try the original lens the same way, if you get spots, it is something in the lens. 

The high f/stop puts everything into sharper focus (dust) and the white wall, slow exposure, out of focus lens, keeps anything but the dust out of focus.

 

+1