Dust


ChairmanMichael

Link Posted 29/01/2012 - 18:10
Does anyone have a major problem with dust and specks on images? No matter how I clean the lens with one of those little blowers, I've set the camera to shake on start-up as well, but dust and specks always appear. It's very frustrating.
Regards,
Michael

ChrisA

Link Posted 29/01/2012 - 18:21
Dust on the lens only very rarely becomes apparent on the image.

Are the dust specks in the same place on every image? Are they a lot more apparent at small apertures than large ones?

If so, it's on the sensor, not the lens.

You have three choices:

- Blower (just tends to move dust around, except with very large lumps)
- Arctic Butterfly (search for it - expensive, but good for dust that isn't stuck)
- Wet clean (swabs and fluid - sounds scary but isn't.)

There are lots of threads giving excellent advice on this one on this forum.
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Last Edited by ChrisA on 29/01/2012 - 18:21

ChairmanMichael

Link Posted 29/01/2012 - 18:25
its strange as I have shots where dust is present but then on the next they are not, even when taking shots of sky etc and I haven't changed the lens. I've been out all day today and 90% of my shots are cream crackered
Regards,
Michael

ChrisA

Link Posted 29/01/2012 - 18:31
ChairmanMichael wrote:
its strange as I have shots where dust is present but then on the next they are not, even when taking shots of sky etc and I haven't changed the lens. I've been out all day today and 90% of my shots are cream crackered

Post a couple so that we can have a look.

As I say, sensor dust is a lot more obvious at small apertures. And on plain backgrounds.
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Last Edited by ChrisA on 29/01/2012 - 18:32

Gwyn

Link Posted 29/01/2012 - 18:47
Unless the dust spots are very extensive you can clone them out easily enough to save your photos from today.
Chris has asked a couple of pertinent questions about the nature of the dust spots, and pointed out when they are most visible.

Maybe you could post a couple of examples so we can help you further. Do read Chris's questions and come back with an answer.

ChairmanMichael

Link Posted 29/01/2012 - 19:40
How do I post an image to the forum?
Regards,
Michael

ChrisA

Link Posted 29/01/2012 - 20:11
ChairmanMichael wrote:
How do I post an image to the forum?

In anticipation of your question, I posted a link to the 'how-to' notes on exactly that in my earlier reply.
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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JAK

Link Posted 29/01/2012 - 21:36
The K-5 has a 'Dust Alert' setting (in screen 4 of the Set-up menu)

Use that by pointing the camera at a blank wall and it will save a dust alert image. It's fully explained in the camera manual.

Should help prove it one way or the other.

John
John K

Gwyn

Link Posted 29/01/2012 - 21:57
JAK wrote:
The K-5 has a 'Dust Alert' setting (in screen 4 of the Set-up menu)


Interestingly it has never worked for me. Dust bunnies all over photos, clearly on the sensor - I can see them with my sensor loupe - but Dust Alert doesn't .

JAK

Link Posted 29/01/2012 - 22:25
Strange
John K

jeeess1967

Link Posted 30/01/2012 - 12:57
Hi, The best way i think to clean the spots is wet cleaning with swab and fluid. It really works.

Regards,

Jeeess
K-5, K-7 and K10D, Pentax 18-135 WR,18-55 WR,Pentax 28-105,Sigma 28-300, Sigma 28-80 (Macro) and Pentax 50-200 WR.

PeterMac

Link Posted 30/01/2012 - 16:49
I thought I had dust spots on my sensor, but on closer inspection of my lens (18-55 mk2) I notice a fair amount of dust on them and there's none on the Dust Alert screen. Looks like the dust is on the 2nd element from the back of the lens. Much the same problem as Gwyn describes above.

What's the best way to clean this lens, or is it bin fodder?
Pentax K20D, Pentax 18-55mm II, Pentax M 50mm 1: 1.7, Super Paragon 1: 2.8 24mm Macro, Pentax smc DA 50-200 mm F4-5.6 ED
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ChrisA

Link Posted 30/01/2012 - 18:00
PeterMac wrote:
but on closer inspection of my lens (18-55 mk2) I notice a fair amount of dust on them

This proves nothing. Dust on the lens does not appear as a speck on the image.

Quote:
and there's none on the Dust Alert screen.

This also proves nothing. The dust alert is not guaranteed to show up sensor dust, as Gwyn has mentioned.

Take two pictures, one with each of two lenses, of featureless blue sky or cloud. At small aperture (eg F22), thus ensuring that the shadow cast by the speck of dust on the sensor is as small as possible.

Upload the pictures to your computer, and increase the contrast dramatically, thereby making the specks a lot easier to see.

If the specks are in the same places, it is sensor dust.

Quote:
What's the best way to clean this lens, or is it bin fodder

If you're really convinced the problem is the lens, I'll be more than happy to take it off your hands. Heck, I'll even pay the postage.
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Pentax K-3, DA18-135, DA35 F2.4, DA17-70, DA55-300, FA28-200, A50 F1.7, A100 F4 Macro, A400 F5.6, Sigma 10-20 EXDC, 50-500 F4.5-6.3 APO DG OS Samsung flash SEF-54PZF(x2)
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Last Edited by ChrisA on 30/01/2012 - 18:02
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