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K20D hot pixels when remote mode on

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Han S Kim

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Just found that using a remote control (3 sec.to shoot) with internal flash produces unbelievable lots of hot pixels.

Could you please take a test and report the results? Not so sure this is just my problem or a general bug in K20D.

Damn frustrated right now but wish this BUG is firmware upgrade patchable.

BTW, am I the first one to report this kind of problem?! I've searched the hot hot pixel issues and normally haven't encounter the serious hot pixel problem yet...

--
...' I only shoot in RAW '
 
how many images have You taken with K20D? If few then please perform pixel mapping and forget about this issue IMO (taken around 1K images with remote 3sec and 2sec MLU mixed- and can not detect any hot ones :-)... but my first tryouts had some- remapped and now after 4K ones simply zero...
Best and happy shooting, JR
 
It seems when dark frame NR does not kick in at certain times,hot pixels appear,i have noticed on a few occasions, when shutter speed is between 2&3 seconds.I think this is why Pentax will not give the option to turn off NR on long exposures, to mask this potential problem,which should not be. ????

Cheers !
 
NR was set to OFF, and FYI my remote controller is from 3rd party.

Wonder if 3rd party remote controller IR signal somehow interferes with
K20D CMOS? Had no problem with K10D though....

--
...' I only shoot in RAW '
 
UPDATE: Those blue pixels (100+) always show up in the exact same position, meaning that they are rather dead/stuck pixels not hot ones.

So why is so? I have no idea.

I tested with external strobe and got the same results. (both internal-generated JPGs and RAW-dcRAW_processed.)

Only guess is that the factory-level stuck pixel mapping is non-working at all.

In terms of hot pixels, after intensive use of Live View, I still haven't found one yet. So the subject line is wrong but I have strange bug. For now, I'll just forget to use remote(3 secs) with strobe.

--
...' I only shoot in RAW '
 
Han S Kim said:
UPDATE: Those blue pixels (100+) always show up in the exact same position, meaning that they are rather dead/stuck pixels not hot ones.
Click to expand...
Han S Kim said:
Only guess is that the factory-level stuck pixel mapping is non-working at all.
Click to expand...
Han S Kim said:
In terms of hot pixels, after intensive use of Live View, I still haven't found one > yet. So the subject line is wrong but I have strange bug. For now, I'll just forget > to use remote(3 secs) with strobe.
Click to expand...
You are correct in the fact thier are dead pixels, many times people use the term hot pixel but it is two very different problems, a dead or stuck pixel can show different colors but they are always in the same place, even my 3 year old Kodak P880 had a pixel mapping feature that maps out dead/stuck pixels. This is an old feature not new to the K20. Hot pixels can show up at random anyplace anytime and cannot be mapped out before hand because how do you know where they are going to be, and they are caused my many factors. So if the K20 did have a hot pixel issue its not a simple matter of using the mapping function, it must be done afterwards in PP and usually is.

But to my point how can you have dead or stuck pixels that only show up using the remote delay, that sounds imposible to me.

--
jamesm007
Samsung GX10, Sigma 17-70mm, 70-300mm APO
http://s195.photobucket.com/albums/z77/jamesm700/
 
OK, I'm having the exact same problem with self-timer (2 sec) too.

Set self-timer (2 sec) mode with internal or external strobe set on,
shoot and I have starry starry night....

Since no other K20D users seem to share this buggy problem,
I plan to return my body tomorrow, assuming mine is defective. :-(

--
...' I only shoot in RAW '
 
Have you tried the pixel mapping feature yet?

I'd do this before returning the body.

bazz.
 
sir_bazz said:
Have you tried the pixel mapping feature yet?

I'd do this before returning the body.

bazz.
Click to expand...
I did twice, and it did remove two dead pixels shown in non-problematic JPGs.

But JPGs generated within self-timer(2sec)+strobe/remote(3sec)+strobe setting
nonetheless show huge amount of dead pixels. (can't even count them up)

--
...' I only shoot in RAW '
 
Han S Kim said:
sir_bazz said:
Have you tried the pixel mapping feature yet?

I'd do this before returning the body.

bazz.
Click to expand...
I did twice, and it did remove two dead pixels shown in
non-problematic JPGs.

But JPGs generated within self-timer(2sec)+strobe/remote(3sec)+strobe
setting
nonetheless show huge amount of dead pixels. (can't even count them up)
Click to expand...
Can you post some example pictures? It definitely sounds like a problem with the sensor though, so would be a candidate for returning. AFAIK a "few" dead pixel are expected but not huge amounts (I don't know if Pentax has a specified max number).
 
cycoj said:
Han S Kim said:
sir_bazz said:
Have you tried the pixel mapping feature yet?

I'd do this before returning the body.

bazz.
Click to expand...
I did twice, and it did remove two dead pixels shown in
non-problematic JPGs.

But JPGs generated within self-timer(2sec)+strobe/remote(3sec)+strobe
setting
nonetheless show huge amount of dead pixels. (can't even count them up)
Click to expand...
Can you post some example pictures? It definitely sounds like a
problem with the sensor though, so would be a candidate for
returning. AFAIK a "few" dead pixel are expected but not huge amounts
(I don't know if Pentax has a specified max number).
Click to expand...
I really hated to post a sample image coz I haven't figured out whether it was my body only which is defective or not. Guess it's just my K20D defective. So here it goes.

Screen capture from the photoshop cs3.

You can see that 100% cropped area only represents less than a 5% of total picture area but already find lots of dead pixels. These pixels are all over the picture randomly distributed.



--
...' I only shoot in RAW '
 
Han S Kim said:
You can see that 100% cropped area only represents less than a 5% of
total picture area but already find lots of dead pixels.
Click to expand...
BTW those are not dead pixels, they are hot pixels.

Moreover, you have to give EXIF details (at least aperture, shutter speed, ISO, EV comp.) if you want any useful replies

Laurens
 
Laurens said:
Han S Kim said:
You can see that 100% cropped area only represents less than a 5% of
total picture area but already find lots of dead pixels.
Click to expand...
BTW those are not dead pixels, they are hot pixels.

Moreover, you have to give EXIF details (at least aperture, shutter
speed, ISO, EV comp.) if you want any useful replies

Laurens
Click to expand...
Hot pixels shown up exact same place every time I take different pictures?
Well, I'm not so sure about that.

Anyways, here's resized original picture which has EXIF informations.

ISO 200, F2.8, 1/60th sec,internal flash on, taken with 40 limited



--
...' I only shoot in RAW '
 
Dead pixels would appear as black spots if you shot a white paper. Deads is dead. No color, not white.
Stuck pixels are just perminent "hot pixels"

Hot pixels can be stuck (stuck at all exposure/iso's ect) or, to create more confusion "transient". ;)

Transient hot pixels always increase w/ exposure time. That's what the NR feature is for.
http://en.wikipedia.org/wiki/Dead_pixel

Now the white pixels are a bit iof a mystery due to the fact that you need at least 2-3 "stuck" pixels to create a white one. Unless 1)Software is mapping "dead" pixels to white
2)Software is "decoloring" stuck or hot pixels
At east thosae are my theories:
http://www.mediachance.com/digicam/hotpixels.htm
http://photo.net/bboard/q-and-a-fetch-msg?msg_id=00EjGr

--
360 minutes from the prime meridian. (-5375min, 3.55sec) 1093' above sea level.

'The exposure meter is calibrated to some clearly defined standards and the user needs to adjust his working method and his subject matter to these values. It does not help to suppose all kinds of assumptions that do not exist.'
Erwin Puts
 
I thought I'd test my new K20D. Here is what I find:

First, I tested at ISOs of 100, 200, 400, 800 with JPEGS at best setting

1) Sensor never mapped. NR at high OFF
No pixel issues at single shot or 12s
White pixels (not sure if hot or ??), in pretty small numbers, only at
2 second timer, at ISO 400 and 800. I'd guess maybe 20, most very small

2) Above, with High ISO NR set at weak

This did not seem to change the 2 Second pixel issue

3) Mapped my sensor, reduced the overall number of white pixels

Which only show up, in very small numbers (5 in total?) at higher ISOs (400-800),
ONLY at 2 Second timer setting. Not at single and not at 12 second.

Something is clearly going on when shooting using the 2 second timer, but it's frankly not that big of an issue with my sensor. I have not used my camera very much yet.

To avoid the issue, of course, do not use the 2 second timer until Pentax (hopefully) comes up with a firmware fix. This should be easy, since there are no problems at other settings. I really happy with the image quality of the K20D...outstanding. So I would buy this camera regardless.
 
robert james said:
I thought I'd test my new K20D. Here is what I find:

First, I tested at ISOs of 100, 200, 400, 800 with JPEGS at best setting

1) Sensor never mapped. NR at high OFF
No pixel issues at single shot or 12s
White pixels (not sure if hot or ??), in pretty small numbers, only at
2 second timer, at ISO 400 and 800. I'd guess maybe 20, most very small

2) Above, with High ISO NR set at weak

This did not seem to change the 2 Second pixel issue

3) Mapped my sensor, reduced the overall number of white pixels

Which only show up, in very small numbers (5 in total?) at higher
ISOs (400-800),
ONLY at 2 Second timer setting. Not at single and not at 12 second.

Something is clearly going on when shooting using the 2 second timer,
but it's frankly not that big of an issue with my sensor. I have not
used my camera very much yet.

To avoid the issue, of course, do not use the 2 second timer until
Pentax (hopefully) comes up with a firmware fix. This should be
easy, since there are no problems at other settings. I really happy
with the image quality of the K20D...outstanding. So I would buy
this camera regardless.
Click to expand...
What were your shutter speeds? Ever slower than 1/30th second? If so long exposure NR kicked in.

I definitely have more than a few. They don't seem to be as bad as the OP in the other thread ( http://forums.dpreview.com/forums/read.asp?forum=1036&message=28055431 ) experiences but it's close.

Chris
 
Yes, Remote (3 sec to shoot) lock the mirror up in advance. (Exact same as 2 sec delay) So it is quite logical to assume that this remote (3 sec) hot pixel bug is almost identical to 2 sec delay one.
QuixoticTonic said:
Does the 3 second delay with remote lock the mirror up in advance of
shutter/strobe fire? I don't have a remote so cannot test, but I'm
curious because of this thread about it happening with 2 second delay
which does lock the mirror up:

http://forums.dpreview.com/forums/read.asp?forum=1036&message=28055431

Chris
Click to expand...
--
...' I only shoot in RAW '
 
Most the shots were taken at 1/30 or faster. I mapped the sensor one more time, and shot at 1600 iso at 1/60 with the 2sec timer....no hot/white pixels at all. Not one.

I never noticed the number and varied color of unusual pixels in the original post pic. So maybe this is not an issue after all with some K20Ds. I'll do more testing and see if I can reproduce the issue.
 
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