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01-23-2015, 12:41 PM   #1
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Does Dust Alert only work with Pentax lenses?

I haven't seen any dust in the images on my K-5ii -- ever. However, I use dust alert and clean the sensor when it shows something. However, now my new Sigma 30 1.4 Art is showing dust spots that my DA 40 doesn't show and that I can't clean off (with my anti-static brush and blower-- I haven't tried wet cleaning).

Is the Sigma 30 just that much better of a lens resolving dust that the DA 40 can't?

Is the Sigma just not working with Dust Alert?

Should I be concerned enough to attempt a wet cleaning -- something I have never done?

Brian

01-23-2015, 01:17 PM   #2
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Dust Alert shows you dust on the sensor - dust which would show up just as plainly with a Sigma 50mm A as with a TP Special. I'd guess you aren't shooting a plain enough wall, or maybe your lens is just ultra dusty. Does the lens focus down to MFD before taking the shot?
01-23-2015, 01:37 PM   #3
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In my experience both the K-5 and the K-3 may miss some dust specs in the sensor.
01-23-2015, 01:57 PM   #4
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The dust alert feature seems pretty useless when I have used it.

Do you have spots showing up on actual photos, or just in the dust alert?

01-23-2015, 02:32 PM   #5
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QuoteOriginally posted by phoned Quote
The dust alert feature seems pretty useless when I have used it.
Pentax dropped that feature from the K-50, so maybe they concur.
01-24-2015, 01:55 PM   #6
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I agree -- it doesn't always work. If I am seeing dust spots in my photos, I take a couple of shots like this:

F/22
low iso
manually focused to infinity
camera pointed at a plain white wall or ceiling
long shutter speed, move the camera around while the shutter is open

DOF at f/22 is really deep, so with the long shutter speed and waving the camera around (facing the white wall) I can be pretty sure that all details on the wall will be blurred away. Everything else remaining is dust.

Then zoom in at x4 and scan across the image, looking for gray blobs to go after.
01-24-2015, 03:07 PM   #7
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QuoteOriginally posted by Quicksand Quote
DOF at f/22 is really deep,
That is literally the exact opposite of what you want. It's just that your other methods blur everything so much (especially the waving, I like that) that you don't see the wall detail.
01-24-2015, 09:48 PM   #8
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QuoteOriginally posted by Giklab Quote
That is literally the exact opposite of what you want. It's just that your other methods blur everything so much (especially the waving, I like that) that you don't see the wall detail.
Yes, it's pretty much the opposite of what you would want in most ways, but it does really sharpen and darken the sensor dust so you can see it more clearly.

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