Is this dust? Please help!?!?

[sigler]

Greetings,

I have a Canon 10d with ISM 28-135 lens.

Is this dust on the sensor?

http://homepage.mac.com/rsigler/flag.jpg

I cleaned the sensor, and didn't see anything. I DO see dust inside the lens. How do I get in there? Any suggestions? The spots are in the same spots every time...regardless if I'm "zoomed" in or out.

Thanks!

Rob

[thomasmoran]

Rob, I had the exact same problem on my 24-85 canon lens and the camera store I bought it from replaced it the seconded they saw it. If the story you bought the lens from has a good return policy they should give you a new one right way. It seems that on some lenes dust can some how work its way inside the lens and then once that happens you’re screwed. If you are out of the warranty period then I'm sure you can send it to canon and have it cleaned. I'm not sure what that will cost thou. Hope that helps.

Thomas

[lightandlife]

Rob,

It sounds like dust. Changing a lens in unclean environment imports dust into the system. Dust in the body may be sucked into the lens and vice versa, depending on static and magnetic field when handling a camera.

Scientifically, it is difficult to determine whether it was defective when you bought it or some dust got into the lens while you were using it. If it has been used a month or more, the latter is more likely. If you bought the lens recently, perhaps you can return it. You would be the best person to judge whether it was a manufacturer or user problem.

It seems more important to keep clean one's conscience than a Canon lens. If it turns out to be a user problem, I would simply have it fixed. The joy of making a mistake is in paying for it.

If you think it was defective when you bought it and did not notice it at the time, by all means return it.

[chris maddock]

It's not dust in the lens - that would be so far out of focus that it will never show up as discreet specks on the "film"-plane. All dust in a lens will do is reduce contrast and increase the risk of flare.

Those spots are indeed dust on the camera sensor. A search will produce numerous methods of cleaning, apart from that in the manual. I personally use a mini-vacuum cleaner, the type sold for cleaning computer keyboards, holding it just above the AA filter in front of the sensor.

KRs
Chris

[RichardtheSane]

I discovered a good test for checking if specs are sensor dust or not - unofrtunatly b accidnet as the specs showed up while I was messing about with techniques :)
Find a scene that is very well lit and fairly low contrast, mount a zoom lens, and take some 'zooming' exposures. Basically set the shutter to 1 second and during the exposure zoom the lens in. With this the whole image and any dust in the lens would blur away from the centre of the image, however sensor dust would remain crisp and unblurred.
:)

[chris maddock]

Even easier - shoot a clear sky or plain wall at both a large and a small aperture. The small aperture shots will show the dust up nice and sharp, whilst the large aperture ones may not even show them at all.

KRs
Chris

[sigler]

I bought a "blower" and cleaned the sensor...all works fine now :)

I'm a little worried about all of the dust inside the lens. I never take my lens off, and I'm very cautious with all of my equipment.

Thanks

Rob