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05-27-2008, 12:14 AM   #121
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So, proof is at dpreview.com forums:
K20s hot/stuck? pixels: Pentax SLR Talk Forum: Digital Photography Review

Many people replicated hot pixels.

Conditions:
2 seconds shutter delay
High ISO noise reduction OFF
Slow shutter speed NR AUTO
Shutter speed faster than 1/30
ISO - set some low ISO, up to ISO400.
Scene with some dar and some bright parts.

Enjoy hundreds of hot pixels.

05-27-2008, 02:44 AM   #122
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So... children, today's assugnment for 'Gotcha' is...

wallow in 'buyer's remorse'...

OR... consider:

How many times do you need to use your K20D in a manner that requires similar 'conditions' (Edvinas, above)? My answer: NEVER!

Hey... I'm heading out into the real world to have some fun with my K20D. If a 'hot pixel shows its pesky little self, I'll deal with it!

sheeeeesh...
05-27-2008, 03:41 AM   #123
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QuoteOriginally posted by Michaelina2 Quote
How many times do you need to use your K20D in a manner that requires similar 'conditions' (Edvinas, above)? My answer: NEVER!
Wrong answer. Many people use a tripod for landscape pictures. While taking pictures from a tripod most people use 2 seconds delay.
Many people have their cameras with High ISO NR off (it's default K20D setting).

So, those conditions are not some exceptional conditions.

BTW, codiac requested pictures with hot pixels, so he could provide Pentax with those pictures. People find out exact conditions how to get hot pixels. No need to be hostile to those who report what conditions produce hot pixels.

Last edited by Edvinas; 05-27-2008 at 03:47 AM.
05-27-2008, 03:48 AM   #124
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QuoteOriginally posted by Edvinas Quote
Wrong answer. Many people use a tripod for landscape pictures. While taking pictures from a tripod most people use 2 seconds delay.
Many people have their cameras with High ISO NR off (it's default K20D setting).

So, those conditions are not some exceptional conditions.

BTW, codiac requested pictures with hot pixels, so he could provide Pentax with those pictures. People find out exact conditions how to get hot pixels. No need to be hostile to those who report what conditions produce hot pixels.

but how many are going to do it with live view? besides with your finishing comment 'enjoy hundreds of hot pixels' just oozes a negative sentiment and goes a little further than just 'reporting'. so its no surprise you get a comment like that above. though I don't think he was being 'hostile'.


Last edited by séamuis; 05-27-2008 at 03:58 AM.
05-27-2008, 04:13 AM   #125
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QuoteOriginally posted by Michaelina2 Quote
wallow in 'buyer's remorse'...

OR... consider:

How many times do you need to use your K20D in a manner that requires similar 'conditions' (Edvinas, above)? My answer: NEVER!

Hey... I'm heading out into the real world to have some fun with my K20D. If a 'hot pixel shows its pesky little self, I'll deal with it!

sheeeeesh...
Well, it's a good thing that people found out how to reproduce the issue (so that a firmware fix can be proposed) and that the circumstances are fairly rarely encountered so that it doesn't become a huge problem for users.

For sure, these conditions are easily encountered when you test a camera so it would be good for Pentax to work on a fix pretty fast if they don't want to get the reputation of selling a "hot pixel machine"....
05-27-2008, 04:20 AM   #126
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It seems that every K20D have this 2s-self timer bug. The problem is easy to reproduce. Not really related to liveview, iso and high iso noise reduction. I got about 2000 dead pixels (using a dead pixel test tool), pixel mapping doesn't help.
I think they are defective pixels instead of hot pixels because they are almost fixed. So I think it's just a ugly software bug and it should be easy to fix.
05-27-2008, 04:28 AM   #127
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QuoteOriginally posted by séamuis Quote
but how many are going to do it with live view?
You don't need to use Live View. 2 seconds mirror lock-up is the cause of the problem.
05-27-2008, 05:23 AM   #128
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Not sure why some posters think using 2 second delay is unusual... I use my K10D this way all the time.

05-27-2008, 08:24 AM   #129
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Counter Example

QuoteOriginally posted by Edvinas Quote

Many people replicated hot pixels.

Conditions:
2 seconds shutter delay
High ISO noise reduction OFF
Slow shutter speed NR AUTO
Shutter speed faster than 1/30
ISO - set some low ISO, up to ISO400.
Scene with some dar and some bright parts.

Enjoy hundreds of hot pixels.
See this: http://www.steves-digicams.com/2008_reviews/pentax_k20d/samples/IMGP0316.JPG

Inspect the EXIF yourself to learn about hot pixels are not appearing JUST for the above specific condition.

There are also quite some other hot pixel samples in the following page, just go to see by yourself and I cannot post the direct pic links one by one:-

Steves Digicams - PENTAX K20D - Hands on Review

(See the "studio" shots and compare them with others.)
05-27-2008, 11:54 AM   #130
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QuoteOriginally posted by RiceHigh Quote
See this: http://www.steves-digicams.com/2008_reviews/pentax_k20d/samples/IMGP0316.JPG

Inspect the EXIF yourself to learn about hot pixels are not appearing JUST for the above specific condition.

There are also quite some other hot pixel samples in the following page, just go to see by yourself and I cannot post the direct pic links one by one:-

Steves Digicams - PENTAX K20D - Hands on Review

(See the "studio" shots and compare them with others.)
Checked one studio shot at 400 12 hot pixels... Big whoop. Go away your too fussy..
The main concern for most is if there are dozens and dozens, which appear w/ the 2 sec delay..
05-27-2008, 12:59 PM   #131
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I had posted a sample of hot pixels with my K20D in the other thread here, following the 2s mirror lockup procedure.

I used ISO400, 1/15s and NR weak. Still got hot pixels. I reported earlier not to have hot pixels.

https://www.pentaxforums.com/forums/pentax-news-rumors/26955-officially-emerg...tml#post252551

So, the hot pixel with 2s delay seems to be real.


BTW, for any tripod users... I guess it would suffice to set long exposure noise reduction from AUTO to ON to workaround this particular issue.
05-27-2008, 01:12 PM   #132
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I had posted the findings about hot pixels of German magazine c't:

https://www.pentaxforums.com/forums/251596-post79.html

Meanwhile, they have added an online comment:
heise Foto - Zweifacher Weltrekord: Pentax K20D und Samsung GX-20 im Test

It contains this important sentence:

"According to Pentax JAPAN, the phenomen [the intermittent hot pixels, edt.] is due to an erraneous basic setting of the sensor as carried out during manufacturing. Therefore, the sample is faulty and should not have escaped into circulation. Another unit which was made available at short notice, did not show the phenomenon. It only had a few ordinary hot pixels which could be mapped out using the corresponding built-in camera function. The duration of the use of LiveView during our after tests had no significant impact on number or intensity of hot pixels. Samsung GX20 and Pentax K20D now show the same level of hot pixels which is in a range we are used to. [...] The visual judgement on category "other artifacts" has now been improved by two points to be "good" now."


So, we have two phenomena:

(1) Random hot pixels in some tested units which are manufacturing anomalies not normally seen in customer shipments

(2) 2s mirror lockup hot pixels due to missing dark frame subtraction.


Phenomen (1) and (2) are different. We should not get confused by mixing them up now...

Last edited by falconeye; 05-27-2008 at 04:25 PM.
05-27-2008, 03:43 PM   #133
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If people chuck a fit this badly over 0.001% of their pixels being bad, I'd hate to see what they do when they get a speck of dust on their lens or sensor.
05-27-2008, 04:56 PM   #134
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I've had my K20D for a little over a week now and thought I'd chime in with another sample. I'm using Dead Pixel Test to provide the counts. Took three shots from both my K10D and K20D at ISO 400, 1/30 sec, 2 sec mirror, dial @ M, with lens cap on. K20D - Slow speed NR = Auto, High-ISO = Off. K10D - Noise reduction = Off.

3 images from K10D ==> count of 6 hot pixels on each
3 images from K20D ==> count of 190, 196, 195 hot pixels respectively

These are using the default value of 60 for the luminance threshold. Is this a reasonable value for this test?

Just posting as an additional point of information. Didn't sync all settings (just those noted above) across cameras so if there are other settings that affect the numbers, please let me know as I'm curious.

One additional set - same parameters as above except drive mode to single instead of 2 sec mirror

3 images from K10D ==> count of 6 hot pixels on each
3 images from K20D ==> count of 2, 2, 1 hot pixels respectively

Last edited by 1979w72; 05-27-2008 at 07:45 PM.
05-27-2008, 05:55 PM   #135
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Anyone contacted Pentax regarding this?

I bought my Pentax K20D recently (last weekend). I was debating myself whether to go with K20D or K200D and finally decided to go with K20D. I haven't actually tried to replicate the hot pixel issue, but little bit annoyed by hearing about that. For my style of shooting, I don't think I will be seeing this problem..but hearing the fact that it exists bothers me a little bit

My question is: Did anyone contact Pentax with these sample tests? What was their response?
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