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07-08-2011, 11:25 PM   #1
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Does this look like sensor stain?

First, I apologize if the attachment doesn't show correctly. I am thinking that I uploaded a valid size but am unsure.

I am a few days into receiving a new K-5 from B-H. The serial number is 3941106. I read somewhere in the Ask B-H portion of the forum that sensor stain issues were completely resolved after serial number 4xxxxxxx or so. I was actually kind of shocked to receive a new camera at this date with such a low serial number.

I ran some tests to check for sensor stain and they all show a very small diagonal speck in the upper right corner. The tests I ran were on the Enticing the Light website which was referenced from one of the forum posts. The set up is essentially zoomed out and focused to infinity with aperture set to f/40, iso at 100, and EV at +1. I tried other apertures and iso's but they all had the same spec. I also tried to run dust removal but no luck. I will keep running some tests to see if I can get a clearer resolution of the speck, but I am just wondering if it looks similar to others that have had stains.

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07-09-2011, 12:07 AM   #2
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It is dust. Syain would be like halo'ed,
07-09-2011, 12:18 AM   #3
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QuoteOriginally posted by Kenn100D Quote
It is dust. Syain would be like halo'ed,
Yes, I have seen pictures of the stains with the halos. I just can't get this picture to sharpen any further using Photoshop or the Pentax utility. So, I am wondering if it were sharper would it show halos? The camera is set to the highest resolution and quality. Raw or jpg ends up looking the same.

The dust removal function doesn't do anything about this. I guess that I should try a rocket blower. Is it common to receive a camera with dust on the sensor? I put the lens on as soon as I unpacked it and haven't taken it off once.
07-09-2011, 01:43 AM   #4
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The shape of the spot looks really like a dust, not a sensor stain.
The stains usually show around f/16. At f/40 you would see them precisely. Have you any 100% crop of the area ?

07-09-2011, 02:06 AM   #5
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QuoteOriginally posted by ZEPsikopat Quote
The shape of the spot looks really like a dust, not a sensor stain.
The stains usually show around f/16. At f/40 you would see them precisely. Have you any 100% crop of the area ?
It must be dust because I can't get it to appear like the typical stains with halos. It appears about the same at 100% crop. Funny that I didn't get anything when I mapped the dust. I will try the rocket blower after I get one. I really don't want to get into touching the sensor. If the blower doesn't work, I will have to put some thought into what to do. I still have time to return the camera and I also have an extended warranty. I don't think that I will need to resort to either of those but I guess that I have options.
07-09-2011, 04:22 AM   #6
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Unfortunately dust in DSLRs is a fact of life.

It's not a fault as such so I wouldn't have thought B&H would change it.

In any event dust can strike at any time; you'll just have to (a) be as careful as possible when changing lenses, (b) learn how to remove dust using (i) a blower (although you're just as likely to simply succeed in moving it elsewhere within the body), (ii) a Visible Dust Artic Butterfly or (iii) swabs, or (c) learn how to remove it in post production.
07-09-2011, 06:07 AM   #7
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Looks like dust, but . . .

If it's a stain, it will likely spread over time. Keep your eye on it.

I use the wet swab method to remove dust when it gets really bad -- when multiple specks start showing up. Dust is inevitable with zoom lenses.

If your dust speck remains small like that, try a rocket blower. If that doesn't work, you can remove the speck from your pictures quickly and easily with the clone tool in Photoshop Elements.

The other posters are right: dust is a fact of life with DSLRs.

07-09-2011, 08:03 AM   #8
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As others have said here, sensor dust is a fact of life. Tiny dust spots are probably best dealt with in post-processing.
07-09-2011, 08:56 AM   #9
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The dust removal system in the K5.....if it is as good as my K20D was, I will never have a dust problem.Tens of thousands of shots and never a lasting dust problem, the system cleaned them every time.
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07-09-2011, 09:01 AM   #10
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That's a stain (and the camera has been replaced by Pentax).

07-09-2011, 09:45 AM   #11
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QuoteOriginally posted by JeffJS Quote

That's a stain (and the camera has been replaced by Pentax).

Thanks. I saw your post a while back so I took a similar shot of one of my guitars. I didn't see anything that resembled your pattern, so I thought that everything was OK. Then I ran the test described on Enticing the Light and saw this speck. I agree with everyone that this must be dust. I have to say that I am a little dissapointed that the dust shake feature doesn't help, but I have noticed that others have posted that most times it has no effect.

Off to locate a rocket blower. Hopefully that will blow the thing to high hell.

I also must say that the Pentax Forum has some great members. I have done many searches in the short time that I have been interested in Pentax DSLR's. There are lots of good posts and I find none of them smack of ego generated BS. All very helpful.

Edit: I also downloaded PhotoMe and checked the manufacture date. It was just a few months back - 2/7/2011. So, if Pentax had corrected the sensor production/assembly problem as someone has said, I would have expected that my camera would have been manufactured many months earlier if it actually had the stain problem. There were some posts about strange serial number sequencing, so obviously the serial number means little.

Last edited by lammie200; 07-09-2011 at 10:08 AM.
07-09-2011, 10:26 AM   #12
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QuoteOriginally posted by lammie200 Quote
Thanks. I saw your post a while back so I took a similar shot of one of my guitars. I didn't see anything that resembled your pattern, so I thought that everything was OK. Then I ran the test described on Enticing the Light and saw this speck. I agree with everyone that this must be dust. I have to say that I am a little dissapointed that the dust shake feature doesn't help, but I have noticed that others have posted that most times it has no effect.

Off to locate a rocket blower. Hopefully that will blow the thing to high hell.

I also must say that the Pentax Forum has some great members. I have done many searches in the short time that I have been interested in Pentax DSLR's. There are lots of good posts and I find none of them smack of ego generated BS. All very helpful.

Edit: I also downloaded PhotoMe and checked the manufacture date. It was just a few months back - 2/7/2011. So, if Pentax had corrected the sensor production/assembly problem as someone has said, I would have expected that my camera would have been manufactured many months earlier if it actually had the stain problem. There were some posts about strange serial number sequencing, so obviously the serial number means little.
I have my shaker set to run on startup. I honestly couldn't tell you if it's doing anything or not. If it is, then I never see the result. If it isn't then I must live in one of the cleanest environments on earth (I don't). Once in awhile I'll get the stray spec that the shaker doesn't knock off but a quick blast with the blower takes care of it. With both the K7 and now the K5, I have never had to Touch the sensor to clean it.

When I saw the stain in the photo, I already knew it was likely (mine was one of the first built) so I simply contacted Pentax and got the ball rolling. I'm still a little concerned because my replacement is built right near the end of the period they say is at risk. I've taken twice as many shots with the new one as I did the first one however and so far so good. Just to be safe, I extended the warranty by 2 years when B&H was selling them for $20.

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