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09/17/2005 08:41:43 PM · #1 |
I shot over 10,000 images with my 300D and never (thats never) had sensor dust issues. Am up to 1,000 clicks with the 20D and I'm constantly getting dust on the sensor. Until mow I've just blown the dust around to make things seem better but every change of the lens (cam pointing down) seems to bring more dust.
Am know doing some landscape work (10-22) and find the problem multiplying . Do other peeps that moved from the 300D to 20D find the dust problem worse on the 20D?
Being bold, shall go down the sensor cleaning route but am seriously upset at the added problems that come from the 20D. Oh, and my other niggle with the 20D is the stupid on/off lever, what muppet dreamt that up?
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09/17/2005 08:47:38 PM · #2 |
I got dust at about 8000 on my D70.
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09/17/2005 09:08:02 PM · #3 |
The problem is "multiplying" with the 10-22mm because the DOF is so extreme, I think. I see more dust on my super-wide-angle shots than I do on my telephoto shots from the same session, though I keep it under control. Maybe it's just that there's usually more sky on the 10mm shots, as dust shows up most obviously on broad areas of even tonality.
Robt.
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09/17/2005 09:09:21 PM · #4 |
I had 5000 images on my Rebel before dust was a problem. A professional cleaning took care of it. I have no doubt that the issue was my proclivity for changing lenses. It sounds like you suspect a conspiracy ... ?
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09/17/2005 10:18:37 PM · #5 |
I don't think the camera per-se is more prone to collecting dust, and probably only slightly more likely to show it (due to the slightly smaller pixel pitch). What is probably the biggest contributor is the fact that you're shooting landscapes, which, as Robert pointed out, often contain large areas of relatively constant tones, and also are often shot at small aperture, where dust is sure to show up if it is there.
Don't hesitate to clean the sensor, it is really a 5-minute task. Look into the copperhill method, it is quick, effective, and "safe when used as directed." It is also one of the most economical methods out there.
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09/17/2005 10:36:11 PM · #6 |
The biggest contributor to dust visibility is small aperture size.
Since you are now doing landscapes ... I'm guessing that you're also shooting at a very small aperture in order to keep the greatest amount of image in focus. And that's when the dust shows up in extreme amounts.
To prove this to yourself ... point your camera at a blank white wall. Set the lens to manual focus and purposely defocus the lens so that there are no "details" in your image coming from the wall. Now take a properly exposed picture at your widest aperture. Try another picture at f/11. And another at your smallest aperture.
Don't worry about needing a tripod ... remember you're not trying to focus on details on the wall so if you shake on a long exposure it doesn't matter.
Now look at each of the three images on your computer. The wide open aperture will probably not show any dust at all. The f/11 image will start to show shadows where the dust spots are (they'll probably be there, but look blurry). And the final image will have extremely obvious dust spots, with very little blur to them.
The reason?
The smaller the aperture, the more the light is coming straight at the sensor. Wide open, the light instead comes at all different angles and basically hides the dust by lighting around it.
Edit: I realize Kirbic said basically the same thing. But I wanted to point out how you could prove this to yourself by taking pictures at different apertures.
Message edited by author 2005-09-17 22:39:37.
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09/17/2005 11:07:06 PM · #7 |
That's interesting. Makes sense. Aperture, not DOF. The good news is, the 10-22mm has HUGE DOF wide-open, so you don't NEED to stop it down much to maintain good range of focus :-) It performs very well, sharpness-wise, at f/5.6 and 8.0. In fact, it's sharper at those mid-apertures than it is stopped way down, it seems to me.
Robt.
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09/18/2005 12:09:11 AM · #8 |
They're ALL dust magnets! Although, I swear my 300d never got a speck and my d70 has at least a few.
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