Black spots

jo30

jo30

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Jo
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Hopefully I've posted this in the right place...

I've got a Canon 500D that's causing me problems with some of my images. On some of the pictures I take there are black/grey spots over the image. It doesn't happen all of the time and mostly happens when there is a solid block of colour in the frame e.g. sky, solid colour background.

I thought it might be dust on the lens or in between the UV filter that I use but I've changed lenses and cleaned the filter so have ruled this out. It leads me to think its something to do with the inside of the camera somewhere on the sensor or on the mirror?? I haven't left the inside of the camera exposed to anything other than when changing lenses but once one is off the other is straight on.

The most puzzling thing is that it's not happening on all of my images. I can take a photograph and the image be spot free but then on the next these black/grey spots occur again.

Example:

View attachment 10036
Does anyone have any ideas whats causing this and how to fix it?

Thanks Jo
 
Dust and crap on the sensor. Try using a wee blower to shift it. If that don't work then get it professionally cleaned. Job done.

You tend to notice this problem more on clean, light, even coloured bg's.
 
Hi Jo it is sensor dust and it will usually show on images when the aperture is above f16 and as you have noticed on plain medium to light coloured backgrounds. In what way have you tried cleaning the sensor?
 
BRASH said:
Dust and crap on the sensor. Try using a wee blower to shift it. If that don't work then get it professionally cleaned. Job done.

You tend to notice this problem more on clean, light, even coloured bg's.
Click to expand...
Fab I'll have a look at that, I thought it might be to do with it but wanted other opinions before I went messing.

sbowler579 said:
Hi Jo it is sensor dust and it will usually show on images when the aperture is above f16 and as you have noticed on plain medium to light coloured backgrounds. In what way have you tried cleaning the sensor?
Click to expand...

That would explain why its all over this image because it was taken at something like f/29 if I remember rightly. I haven't as of yet, any recommendations, of the best way to go about it?


Thank you both.
 
Firstly, no need to ever shoot at f/29! F/16 is pretty much as high as you ever need to go, other wise you hit the limits and start getting diffraction which actually makes the image soft..

As for sensor cleaning, try a rocket blower first, if that doesn't work, but a wet clean kit. Visible dust are my choice, you can buy 4 packs of swabs with a little bottle of fluid. That should be enough to get rid of most of it.
 
Just be careful if you never done before cleaning an sensor,cost about £40 for a shop to do it :)
 
TCR4x4 said:
Firstly, no need to ever shoot at f/29! F/16 is pretty much as high as you ever need to go, other wise you hit the limits and start getting diffraction which actually makes the image soft..

As for sensor cleaning, try a rocket blower first, if that doesn't work, but a wet clean kit. Visible dust are my choice, you can buy 4 packs of swabs with a little bottle of fluid. That should be enough to get rid of most of it.
Click to expand...

I was going along the line that a low f/number give a shallow DoF and didn't want that so went to the opposite, although I do see what you are saying on some of my images. But every day's a school day.

Will definitely look into the methods you recommended.
simonblue said:
Just be careful if you never done before cleaning an sensor,cost about £40 for a shop to do it :)
Click to expand...

Will do, I'll have a google at local shops that offer this service.

Thanks everyone!
 
It's really not that scary to do. £40 will buy you enough to clean your sensor for several years to come.

Just make sure the battery is fully charged and use a light pressure when swabbing, like using a pencil. Put a small amount of fluid on the swab, 2 drops is enough, sweep from one side to the other, turn the swab and go back the other way.. That's it.
 
TCR4x4 said:
It's really not that scary to do. £40 will buy you enough to clean your sensor for several years to come.

Just make sure the battery is fully charged and use a light pressure when swabbing, like using a pencil. Put a small amount of fluid on the swab, 2 drops is enough, sweep from one side to the other, turn the swab and go back the other way.. That's it.
Click to expand...


Despite all rationale, for some reason I still turn into a shaking handed quivering wreck whenever I attempt a sensor clean. It annoys the life out of me as otherwise I have the steady hand of a surgeon.
 
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