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07-06-2008, 08:27 PM   #1
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Hot pixels with *istD

I just purchased a "DEMO" *istD from Adorama. It looked great but I see many hot pixels in my photos, at all ISO settings. Some of them look like they are in the same place each time.

Is this normal? Have I purchased a damaged camera?

Does Pentax repair things such as this?

edited to add: Do the other 6mp cameras suffer from this? (K100D, K100D Super).


Last edited by skid2964; 07-06-2008 at 11:32 PM.
07-06-2008, 08:42 PM   #2
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What are your exposure times? Long exposures will tend to produce hot pixels due to sensor temperature. My K100DS likes to make them in the same spots regularly, though they are somewhat random.
07-06-2008, 08:48 PM   #3
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Now that you mention it, I do see them more in speeds of 1/15 to 1/60th, I examined some faster photos 1/125, etc. Didnt see as many.

I just took some photos with the lens cap on, 15 seconds, not near as many as I saw in the first photos I took when the camera first arrived. Could it have something to do with not being used for a long time?
07-07-2008, 06:28 AM   #4
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QuoteOriginally posted by skid2964 Quote
...
I just took some photos with the lens cap on, 15 seconds, not near as many as I saw in the first photos I took when the camera first arrived. Could it have something to do with not being used for a long time?
Perhaps. If the istD has the Noise Reduction option like my K1x0Ds have then I'd suspect the NR kicked in at 15 seconds and reduced the noise. Pentax is vague as to when NR goes into operation, I can tell on my camera it IS on at 1/2 second and my be on at faster shutter speeds.

As "alohadave" mentioned temperature is a factor. Long exposures, repeated exposures, and ambient temperature affect noise.

Noise is very subjective, depends on the subject matter, exposure, etc and is hard to quantify.

You could post a simple example with the exposure details and those with a better eye then I could tell if it is normal.

07-07-2008, 09:54 AM   #5
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Here is one taken with lens cap on, f/22, 30 second exposure, ISO 3200


Something more realistic, f3.5, 1/500 Exposure, ISO 200
You can see many hotpixels over the background fence.
07-07-2008, 11:19 AM   #6
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Adorama

QuoteOriginally posted by skid2964 Quote
I just purchased a "DEMO" *istD from Adorama. It looked great but I see many hot pixels in my photos, at all ISO settings. Some of them look like they are in the same place each time.

Is this normal? Have I purchased a damaged camera?

Does Pentax repair things such as this?

edited to add: Do the other 6mp cameras suffer from this? (K100D, K100D Super).
I am so sorry that you have been inconvenienced; I can't tell you whether there is a problem with your camera, but we'd like to check it out.

Please can you contact me outside the forum, with your order / invoice number; we can then send you a label so that you can return it to us. [helen.oster@adoramacamera.com]

Sincerely

Helen Oster
Adorama Camera Customer Service Ambassador
07-07-2008, 11:39 AM   #7
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07-07-2008, 11:47 AM   #8
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QuoteOriginally posted by skid2964 Quote
Here is one taken with lens cap on, f/22, 30 second exposure, ISO 3200
(snip)
Something more realistic, f3.5, 1/500 Exposure, ISO 200
You can see many hotpixels over the background fence.
(snip)
W/ my D and the Sony 6mp sensor I noticed increasing hot pixels as the sensor aged. Was replaced by Pentax. Unfortuntely (yet expected) the new sensor had hot pixels, but less of course. Worst part was my "new sensor" had more of an inclination to band
Adorama's offer is generous I guess but I'm not sure you will find one w/ fewer or less distracting. For some reason they are not very obvious in the pictures you downloaded.
Do do what makes you feel comfortable...

07-07-2008, 12:38 PM   #9
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If you zoom in on these you can really see the hot pixels well. They show up bad on a print.

Does the K100D have the same sensor? Are they less prone to this problem?

Helen with Adorama is being very helpful.

QuoteOriginally posted by jeffkrol Quote
W/ my D and the Sony 6mp sensor I noticed increasing hot pixels as the sensor aged. Was replaced by Pentax. Unfortuntely (yet expected) the new sensor had hot pixels, but less of course. Worst part was my "new sensor" had more of an inclination to band
Adorama's offer is generous I guess but I'm not sure you will find one w/ fewer or less distracting. For some reason they are not very obvious in the pictures you downloaded.
Do do what makes you feel comfortable...

Last edited by skid2964; 07-07-2008 at 12:57 PM.
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