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08-19-2009, 04:02 PM   #1
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Help - Spots "They" Say it's not on the Sensor

I have a couple of spots that are appearing on my pictures. I assume Sensor dust and tried to Rocket Blower it no avail. Then I tried swabbing it with the VisibleDust UltraMXD-Vswab 1.0x Sensor Cleaning Swabs Green Series system and cleaner no luck. Finally gave up and brought it in for a 'professional' sensor cleaning. (Have my doubts on how much more professional it was than what I did).

I was given the Camera back saying all was ok. Well the *#&$^% specs are still there. So I drove back to the main branch and showed them. The lady that cleaned the sensor used that magnifying thing and showed me the sensor was clean. It looked clean to me I guess but wtf do I know ?

So if it is not a spot on the sensor what else could it be ? It shows up on all stops. More importantly how or what can do to fix it ?

click on image for larger view

Look in the upper left. If you think it is a spot I can try and clean it again. If it is in the upper left in the picture does that mean it is in the lower left as I am looking at the sensor ?

Could it be something caught between the low pass filter and sensor ? Something on the mirror?


Here are some examples.

Here is it at f7.1


A crop


at f22


a crop


08-19-2009, 04:23 PM   #2
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please bare with me I am guessing that the spot shows up even after you change the lens ? course I dont even know if something inside a lens would effect the picture mind you
08-19-2009, 04:28 PM   #3
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No problem - yes should have mentioned that , it does show up on at least two different lenses so I am comfortable it is not a lens issue.
08-19-2009, 04:35 PM   #4
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Should be on the lower right corner of the sensor I think.

08-19-2009, 04:36 PM   #5
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QuoteQuote:
Look in the upper left. If you think it is a spot I can try and clean it again. If it is in the upper left in the picture does that mean it is in the lower left as I am looking at the sensor ?
Lower right. The image is flipped horizontally and vertically.

You probably won't be able to see it no matter what.
08-19-2009, 04:37 PM   #6
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Looks like sensor dust to me.

The mirror is not in the light path, so it can not be that.

If it is not sensor dust (I think it is), then possibly pixel problems.
08-19-2009, 04:41 PM   #7
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Dave, clean your sensor. Welcome to my world. I have this problem too. It's very visible on my sky images. One trip to Death Valley was all it took for these bad boys to appear on my K10d's sensor. You can get rid of them of course and you can use PS's healing brush tool to address them in your images but they are a PITA for sure.

Tim
08-19-2009, 04:43 PM   #8
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QuoteOriginally posted by daacon Quote
I have a couple of spots that are appearing on my pictures.
[...]
If it is in the upper left in the picture does that mean it is in the lower left as I am looking at the sensor ?
This sure is a dust speckle. They can be very difficult to remove (I once tried to remove a similiarly big one and failed before using the Pentax dust removal kit. The Pentax thing is really great for difficult cases).

But ...

You really must be able to see it on the sensor. Use lot of light, and a loupe maybe. And correct, it should be in the lower left corner of the sensor, when viewed from the mount hole.

(for the lower right corner posters: you may be correct; but did you take into account that the speckle is in the lower right when looking from behind the camera -- which becomes lower left when looking from the front?)

This is a K20D. Maybe, shoot a dust detection image (menu operation) and show the lady. The dust detection image is stored on the SD card (with _dust in the name or so) and so, can be printed out. The dust detection image must be shot against a uniform defocussed background unless you want to see lots of false speckles


Last edited by falconeye; 08-19-2009 at 04:48 PM.
08-19-2009, 04:57 PM   #9
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I am pretty sure it is a spot as well - she was trying to tell me dead pixels , Martians, etc ... told me the phone the Pentax Rep - like that was going to help (hold it closer to the phone and now hit it !!!)

I have tried to clean it myself, thought the professional $70.00 cleaning would be better but you know what , I now know they do not do any better than I do). At the shop I looked through a Loupe with her but like I said wtf do I know? She was sure it was not the sensor (with a bit of attitude I might add - probably turned me off McBains for now but that is a different story )

It does come clean in PP easily but to have to touch every shot (well it does not appear in every shot, like Tim mentions , blue skies, light background, etc...) this is a PITA I need to at least review evey shot closley to see if it is there.

Maybe I will just have to try a different cleaning method. These are the kind of things that really annoy me.
08-19-2009, 04:59 PM   #10
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QuoteOriginally posted by pschlute Quote
Looks like sensor dust to me.

The mirror is not in the light path, so it can not be that.

If it is not sensor dust (I think it is), then possibly pixel problems.
And how does one determine the difference beteeen pixel issues and spots ?
08-19-2009, 05:03 PM   #11
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Flashlight + shortsight then it will be spotted. Use something like Tack-It bought from art store to stick it out then you will have a clean sensor. It will be much less messy then wiping the whole sensor.
08-19-2009, 05:04 PM   #12
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QuoteOriginally posted by daacon Quote
Maybe I will just have to try a different cleaning method.
As I said. Use the Pentax cleaning kit. I really had to press the thing onto the speckle to kill it... So, first, I needed to see it. And second, I increased pressure gradually because it really didn't want to go ... I was actually worried to have damaged the sensor afterwards. I did not
08-19-2009, 05:21 PM   #13
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Typical dost spot, you should have seen how many are on the 5d mk2 from the factory before I cleaned it.
08-19-2009, 05:40 PM   #14
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QuoteOriginally posted by Torphoto Quote
Typical dost spot, you should have seen how many are on the 5d mk2 from the factory before I cleaned it.
I thought it was from the customs having fun with it
08-19-2009, 05:55 PM   #15
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QuoteOriginally posted by daacon Quote
And how does one determine the difference beteeen pixel issues and spots ?
Stuck pixels don't change size when you change the aperture. It would also show up if you shot a frame with the cap on (assuming it's stuck on a particular color or white). A dead pixel would show up as a black pixel (if you even saw it).
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