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Spots at f16


mrphotog

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I have taken shots of a landscape scene that includes sky and notice spots in the upper right corner of the image when using any aperture of f16 or f22. I noticed it first on a Zeiss 35mm f2 but duplicated the problem with the Leica 75mm apo summicron.

 

Has anyone else seen this phenomenon? I've shot the same image from f2 through f16 (on the 75mm) and from f2 through f22 with the Zeiss and the spots only appear at f16 or higher. There is some hint at f11 but they are readily apparent at f16.

 

I checked the sensor and do not see any obvious dust although this was using the Visible Dust lighted magnifier. Perhaps its magnification is not sufficient to see the problem.

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definitively if the behavior is the same with different lenses (i.e. the points in the same position) then there's some dust (could be oil) on the sensor.

If those dot positions are different, then it's dust on the lens.

 

BTW, just a pice of advice: don't shoot @ f16-f22 (nor F11 FWIW), you get diffraction and lower details on your pictures. ;)

Dunno if you were using a DSLR camera before the M, but it's quit common for many who make the switch to ignore them the lenses' differences.

Being smaller, M lenses get diffraction phenomena earlier than DSLR's.

Sean Reid, and me too FWIW, consider F/8 as the last useable diaphragm with almost every lens in the M set.

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Yes welcome! It's annoying having dust but it happens to all of us.

 

Maurizio, I've never seen dust (even caked onto a rear element) show up in shots, it might happen with an extremely wide symmetrical lens like a hologon but diffraction takes care of it on all other lenses and the only effect of severe dust is a lowering of contrast and sharpness.

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Yes welcome! It's annoying having dust but it happens to all of us.

 

Maurizio, I've never seen dust (even caked onto a rear element) show up in shots, it might happen with an extremely wide symmetrical lens like a hologon but diffraction takes care of it on all other lenses and the only effect of severe dust is a lowering of contrast and sharpness.

 

Daniel, I can't really understand what you're telling me, sorry for my english. :(

Anyway, dust particles on the lens show up when you close the diaphragm ring as well as dust on the sensor.

For what that concerns diffraction, I wasn't sayin' that it has something to do with dust or spots on the pictures, I suggested the OP not to use with ease those diaphragms (f16-22) as the consequence is diffraction and lower IQ.;)

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It's not dissimilar to the situation in your avatar pic. If you shoot through a wire fence close up, with a wide aperture, you probably won't see the fence in your photo. It would have to be a VERY large piece of dust on a lens to show up in any photo!

 

Yes I concur: Whenever I forget the lens cap on I always see it in photos! But that is the largest spec of dust one can find

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