"water spots" in large areas of a single color

[zedvictor1]

When a large area of sky is in a photograph, I see what appear to be waterspots in the area, but the glass is clean.  Is this a sensor problem? It happened with my previous Canon DSLR as well. I use the 100-400L lens on a 60D. Thanks.

[ScottyP]

Sounds like dust on the sensor. You tend to see it most on a solid color background like a blue cloudless sky or a white wall.

There are kits and videos on how to clean it yourself, but if there is a camera place near you that will do it, that would probably be the way to go.

[zedvictor1]

Thank-you, Scott.

So I take it that the camera's built-in sensor cleaning is somewhat limited?

[zedvictor1]

I should add, I think, that the spots aren't specs but are quite large and transparent--more like round smudges. I clean them up later with a clone tool, but this is less than ideal.

[RobertTheFat]

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@zedvictor1 wrote:
I should add, I think, that the spots aren't specs but are quite large and transparent--more like round smudges. I clean them up later with a clone tool, but this is less than ideal.

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In principle, it could be lens flare spots, but those are pretty distinctive and not very repeatable, since they depend on the angle of the incident light. They could be actual water spots if the sensor was ever exposed to rain. A few years ago there was a particular Nikon DSLR that had a problem with oil spots; the mirror mechanism was over-lubricated and threw oil droplets onto the sensor. But I've never heard of that happening on a Canon. If a professional sensor cleaning doesn't cure the problem, it would probably be wise to send it to a Canon shop. They're not cheap (unless you're a CPS member), but they do a good job.

[ebiggs1]

You need to post a sample of what you speak.  No body can tell you by guessing.

[zedvictor1]

Thanks, everyone.  I'll try cleaning the sensor.  I have noticed dust specks on trial shots but did not relate those to the larger more transparent blobs, but they could well be the same thing. I'll also attempt to use a larger aperture.

[RobertTheFat]

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@zedvictor1 wrote:

Thanks, everyone.  I'll try cleaning the sensor.  I have noticed dust specks on trial shots but did not relate those to the larger more transparent blobs, but they could well be the same thing. I'll also attempt to use a larger aperture.

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I don't see how using a larger aperture will help the problem. Anything on the sensor is going to be in focus. Defocusing the background won't defocus dirt on the sensor, wherever it is in the image.

[ebiggs1]

If you don't know what you are doing, do not try to clean the sensor yourself.  There are lots of things that do not do well inside of the mirror box if not done correctly.

[MikeSowsun]

These dust spots are more visible at smaller apertures like f/11 or f/16.

If you still see them after you have tried cleaning the sensor, you will need to get it cleaned professionally.   In th mean time just try shooting at larger apertures like f/5.6 or maybe f/8 and you probably won;t see the spots.