How to check for sensor stains?


milamber

Link Posted 14/07/2012 - 16:49
Slightly misleading title as I wasn't sure how to word it!

Checking my Italian photos I can see a number of small sensor stains, particularly against the very blue skies. I thought I had dealt with these before I left, but obviously UK skies weren't blue enough....

I've cleaned the sensor, but am finding it difficult to tell if they are gone or not. No blue skies here and I can't get them to show up either before or after the cleaning, but I know they are/were there.

Any tips on how to check if they are gone in this miserable summer? I've tried a white sheet of paper, but can't see anything. They may well be gone, but I can't say for certain. Nothing shows up in the dust check, but guess they are a different animal.

What causes this? I'm really careful when I change lenses and don't do that often anyway. Can the high heat/humidity do it?

Any advice appreciated

wvbarnes

Link Posted 14/07/2012 - 17:34
Sticky pollen?

milamber

Link Posted 14/07/2012 - 17:38
wvbarnes wrote:
Sticky pollen?

No - my nose attracts all the pollen from a 3 mile radius during the hayfever season

steven9761

Link Posted 14/07/2012 - 17:44
Do you have any plain pastel-coloured walls in your house? If so, try taking a shot of a plain section of the wall that is evenly-lit and coloured. Either that, or turn on your a/v channel on your tv. Most of the newer screens will display a plain blue background. Whilst not ideal, it may be adequate enough for you to use to check the sensor.

milamber

Link Posted 14/07/2012 - 18:19
steven9761 wrote:
Do you have any plain pastel-coloured walls in your house? If so, try taking a shot of a plain section of the wall that is evenly-lit and coloured. Either that, or turn on your a/v channel on your tv. Most of the newer screens will display a plain blue background. Whilst not ideal, it may be adequate enough for you to use to check the sensor.

Cheers - hadn't thought about the blue TV background - I'll give it a try. The only pastel coloured wall I have needs re-painting and probably looks worse than the sensor stains!

Much appreciated, thanks

Gwyn

Link Posted 14/07/2012 - 18:27
If you post an Italian picture here the experts in sensor stains and crud, and the difference between the two, can probably tell you straight away which you have.

milamber

Link Posted 14/07/2012 - 18:47
Italian picture as requested - embarassed to post it really! It's the one that shows the stains the worst - there might be some lower down, but I can't see them.


Gwyn

Link Posted 14/07/2012 - 18:58
OK that is not staining - that is crud. You need to clean your sensor .

milamber

Link Posted 14/07/2012 - 19:57
Thanks - not sure 'crud' is any more reassuring I've cleaned the sensor, but still struggling to test the image. Probably have to wait for a blue sky - that will be next June then....

silverfox

Link Posted 14/07/2012 - 20:06
I agree with Gwyn, they look like dust spots to me. They always show up more against the sky. Sensor cleaning time or spot removal tool

cbrog

Link Posted 14/07/2012 - 20:25
You had to climb Vesuvius to find a blue background?

Now THAT is dedication -



Roger

milamber

Link Posted 14/07/2012 - 20:35
I take my hobby VERY seriously

I've cleaned the sensor and it looks spotless. When I do the dust check it's completely white, but I still have a few spots on the photos. Could it be anything else? It's the same on both of my PKA lenses so can't be the lens.

Could it be dust on the mirror?
Last Edited by milamber on 14/07/2012 - 20:49

ChrisA

Link Posted 14/07/2012 - 21:37
milamber wrote:
I've cleaned the sensor and ....

You haven't said how. To be honest, whatever you're using isn't very effective.

Quote:
...it looks spotless.

'Looks'? How are you judging it to be clean, since it very obviously isn't?

Quote:
Could it be anything else?

No. It's ordinary specks of crap on the sensor. Nothing a proper clean won't sort. Search for 'arctic butterfly' (a highly rated dry cleaning device that removes particles that are not adhered to the sensor) and 'swabs' (used for a wet clean, essential when the muck is stuck).

Quote:
Could it be dust on the mirror?

If you think for a moment about where the mirror is during the actual exposure, you will realise instantly that no, it couldn't.
.
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)
.

milamber

Link Posted 14/07/2012 - 21:56
Well thanks, I think. I'm not sure your reply needed to be quite so patronising. I'm judging it to be clean because the sensor dust check doesn't show anything.

I've been around long enough to take that sort of reply with a pinch of salt, but I doubt a new member would come back again.

Gwyn

Link Posted 14/07/2012 - 22:18
milamber, I have experienced the dust check showing it to be clear but there still be stuff on the sensor.
I use an Arctic Butterfly brush, and now also have their loupe to check the sensor is clean.

I don't know what you used, but I would try cleaning it again, maybe with wet swabs if you have tried a brush.
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