[dougieazar]

Hi people. I have here a rather perplexing problem and one which all you techies out there might, I said just might, have an answer too. I have a recurring spot on my images and always in the same place. Ok so far nothing new. I took the lens off and thoroughly cleaned it. turned on the camera and cleaned the mirror then for sensor cleaning mirror up I used my little blower and whiffed at the sensor to remove dust etc. I did not wipe it with a dauber. Put the lens back on and took 3 sequences of exposure compensation shots. Three shots each for a total of 9 shots. These were taken of a white piece of paper. The spot was visual in 3 out of nine shots. It only shows up in the underexposed image. The other two are clear. Why is that spot only there once and on under exposed image?...........thanks in advance...............Douglas

[bertwert]

The best way to see dust spots is to close the aperture down all the way and shoot at a clear bright surface, well out of focus - any spots appearing there will be due to dust. That's what I do when I think there's some spots on my image, to confirm it's dust, and then go about getting rid of them if that's the case.

It could be that the spots were visible in the underexposed shots due to the aperture being more closed down in them - also play with contrast and exposure in an image editor and you may have the spots appear in the other shots.

[bschriver11]

On my K-3ii there is an option to check for dust on the sensor and it works very well. Not sure what camera your using?

[Michail_P]

I once in a while use dust removal... it's ok till now. If the particle is so consistent then you might need to clean your sensor. If you see it in a shot then it's probably there but your aperture was open enough to blur its image.

[pschlute]

You have a stubborn spot on the sensor. You should clean it yourself or have a camera shop do it.

Cleaning the mirror can not affect dust on the sensor. Best advice is to never touch the mirror.

[ramseybuckeye]

Sounds like you need to clean the sensor, the blower won't always get it off.

[jbinpg]

Some plant pollen is heavy and sticky. If it gets on your sensor, it can be hard to remove. A cleaning with a sensor cleaning kit can be a good start.

[Bob 256]

Maybe an example image?

[kiwi_jono]

Sounds like sensor dust to me but would need to see photos to be more sure. Shooting with a lens stopped down to minimum aperture (f22 - f32 say), focus to minimum distance and take a shot of something further away with mid tones (I often point at a deep blue sky or shaded ceiling), shows it up pretty well. If the background is too bright, the spots won't show up well (if at all).
I remember with my K-5 I used to have to regularly clean the sensor (typically annually at least). However the dust removal on my K-1 seems to be much better - in 5 years I have only had to clean it once.
A sensor needs to be cleaned very carefully with the right products (I use sensor swabs myself), there are lots of articles on line on how to do it properly, and if unsure getting it cleaned professionally is always a good option.

[BarryE]

Just be aware - dust spots can just disappear. I had an annoying one that didn't blow off and I hadn't got round to using a wet/sticky swab cleaning method. Then I noticed it had just vanished. I suspect it was eventually dislodged by the sensor's vibrating self-clean. So maybe wait a while ...