Inspection after sensor cleaning?


niklas

Link Posted 02/10/2009 - 19:28
A week ago or more I had some heavy dust issues in my K20D.
It was not able to eliminate with the build in dust removal shake function through the menu.

I spend all afternoon, with the remidies at hand, trying to solve this.
I used a brush and airball with marten hair (I think).
My magnifier for looking in was an 8X magnifier as the one used for negatives on a lightboard.
I also had had a magnifier for when repairing watches.

Since the dust issue stayed there, even though moving from one area to another on the sensor, in the end I grabbed something I should never have done, A handheld battery driven compressor.

Auch.
It removed the dust but small particles of oil was blown out together with the air and they were now stuck on the sensor.

So I left my camera on the shelf and went on eBay and other places ordering Eclipse E2, Sensor Swab 2, Giottos Rocket Air Blower and some Pentax original cleaning thing working as a sticky thing to remove known spots on the sensor.

To day I got the Eclipse E2 and Sensor Swabs.
So I started cleaning sensor.
And it obviously helped.

Inspection is done by photographing a clear blue sky and go 100% on a good CRT screen.
Cleaning were done in 3 tempi with inspection in between.
Less and less spots occured on the clear blue sky photos.
Every inspection consisted of 2-3 photos of different parts of the sky without taking off the lens.
Last inspection today showed a completely spotless sky on the first shooting.
However, on second photo I found a spot on the sky that could look like dirt/oil.

My Question is:
If inspection photo #1 is spotless and inspection photo #2 have a spot, will this spot be some element on the sky, like a very unsharp bird or insect?

Or am I doing this all wrong?

Niklas
15mm - 450mm equivalent, and still can't reach...

Anvh

Link Posted 02/10/2009 - 21:24
The way to do it is use the highest F-number of the lens and overexpose the photos quite a lot.
Any dust on the sensor but also the lens will be shown then.
Stefan


K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ

niklas

Link Posted 02/10/2009 - 21:31
Anvh wrote:
The way to do it is use the highest F-number of the lens and overexpose the photos quite a lot.
Any dust on the sensor but also the lens will be shown then.

Thanks a lot.
I will do that next time I get the chance.
It is not dust, though, that worries me.
It's stains on the sensor from oil and other particles.

Niklas
15mm - 450mm equivalent, and still can't reach...

Anvh

Link Posted 02/10/2009 - 22:17
Everything on the sensor (lens) will become visible then.
The high f-number insures that the light that falls on the sensor is perpendicular to it, so dust or anything else will block the light and will show up.
Stefan


K10D, K5
DA* 16-50, DA* 50-135, D-FA 100 Macro, DA 40 Ltd, DA 18-55
AF-540FGZ

Mannesty

Link Posted 02/10/2009 - 22:30
The K20D has a menu function to show you where the dust is on your sensor.

The Pentax sticky tape will not remove oil from the sensor, Eclipse 2 fluid will.

Don't forget you are not actually cleaning the sensor, but a piece of glass with special coatings on it which, amongst other things protects the sensor from dust. I'm not sure if it's oil proof though
Peter E Smith

My flickr Photostream

niklas

Link Posted 02/10/2009 - 22:36
You are all so very helpful here.
Thank you very much.

Niklas
15mm - 450mm equivalent, and still can't reach...
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