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Can "DeadPixelTest" be trusted entirely ?

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notko said:
That'll be pre v3.6 C1, I guess.
The feature disappeared in v3.6. We'll see if it is back in 3.7
Click to expand...
Exactly. v3.5.2 (and all previous versions) removes hot pixels fantastically as evidenced by the image I posted above. But due to a bug (acknowleged by Phase One) that capability no longer exists in v3.6. So I keep using 3.5.2 for all my long exposure shots and 3.6 for everything else as it has better profiles available(i.e. etcetera v2 from Magne). If v3.7 does not fix the problem I am going to be quite upset.

Al
 
fotografo said:
BTW, what is the yellow area in
your image (below) ? Just curious ...
Click to expand...
Yellow area is glow from the already set sun, this was perhaps taken 8-9pm or so if I remember right.

Al
 
An alpha particle is a helium nucleous emitted at high energy as ionizing radiation from radioactive decay, they come from impurities in your camera. How often they occur depends on what the camera is made out of. Other radiation like beta and gamma particles could also be detected by a digital sensor, for instance you could get a radiation hit from (secondary radiation from) a cosmic ray but these are infrequent.
 
Why are you so concerned with dead and hot pixels? Unless you notice them in regular shooting, they won't matter. Chances are you will get more clutter in your images from noise on the sensor than you will from damaged pixels. Either way, most noise reduction tools will get rid of it anyway, everything from Photoshop to Neat Image, and whatever else you might use.

If you are that concerned with finding a dead pixel or hot pixel, you are going to find one reguardless if it is there or not.

If you really want to find out, take a shot in the dark with the lens cap on. Dead and hot pixels will show up there, but like I said, it doesn't really matter if they are there or not unless you make a big deal out of it..
 
DSPographer said:
An alpha particle is a helium nucleous emitted at high energy as
ionizing radiation from radioactive decay, they come from
impurities in your camera. How often they occur depends on what the
camera is made out of. Other radiation like beta and gamma
particles could also be detected by a digital sensor, for instance
you could get a radiation hit from (secondary radiation from) a
cosmic ray but these are infrequent.
Click to expand...
– Wow! I would have guessed on radiation from space, but the particles comes from the camera material itself! Nothing to do about it then? Put the camera in a inverted X-ray machine or something?! :-)
 
Yeah, exactly. Sensor noise is expected in digital imaging right now - it's one of the tradeoffs. And it's not really a tradeoff given how minor these problems are now, with noise reduction technology and better sensor design. On current generation sensors you are guaranteed to see hot pixels with long exposures, just from minor differences in photosite sensitivity, camera electronics, and heat (infrared radiation inside the camera).

Now stop manically fussing over your cameras and start taking pictures! Any real problems will show up in your photographs, not in extremely sensitive software tests on dark-frames or 500% zoom in photo viewing utilities.
squirrel777 said:
Why are you so concerned with dead and hot pixels? Unless you
notice them in regular shooting, they won't matter. Chances are you
will get more clutter in your images from noise on the sensor than
you will from damaged pixels. Either way, most noise reduction
tools will get rid of it anyway, everything from Photoshop to Neat
Image, and whatever else you might use.

If you are that concerned with finding a dead pixel or hot pixel,
you are going to find one reguardless if it is there or not.

If you really want to find out, take a shot in the dark with the
lens cap on. Dead and hot pixels will show up there, but like I
said, it doesn't really matter if they are there or not unless you
make a big deal out of it..
Click to expand...
--

Amateur enthusiast. Equipment: 1 modern autofocus film SLR, 1 short tele zoom, 1 fast normal lens, 1 russian and 1 german TLR, 1 3.2MP point and shoot digital.
 
Jochum Berg said:
DSPographer said:
An alpha particle is a helium nucleous emitted at high energy as
ionizing radiation from radioactive decay, they come from
impurities in your camera. How often they occur depends on what the
camera is made out of. Other radiation like beta and gamma
particles could also be detected by a digital sensor, for instance
you could get a radiation hit from (secondary radiation from) a
cosmic ray but these are infrequent.
Click to expand...
– Wow! I would have guessed on radiation from space, but the
particles comes from the camera material itself!
Click to expand...
I guess I should have also included radon from the air as a source of radiation that is inside your camera and that you can't avoid; but testing your house for radon and adding abatement if necessary is a good idea (since the alpha particles are not good for your lungs either). I am not sure how frequent each type of radiation hit is but I remember that the geiger counter I played with back when I was in school didn't stay silent for a very long time.
 
DSPographer said:
I guess I should have also included radon from the air as a source
of radiation that is inside your camera and that you can't avoid;
but testing your house for radon and adding abatement if necessary
is a good idea (since the alpha particles are not good for your
lungs either). I am not sure how frequent each type of radiation
hit is but I remember that the geiger counter I played with back
when I was in school didn't stay silent for a very long time.
Click to expand...
– A Geiger counter, played with one a year ago, it ticked almost every second if I remember right, so it is those that makes some of the hot spots?!
If I moved it over my heart it ticked faster though, guess I was contaminated?!
No radon here though, living on second floor in a old wooden house!
 
walter23 said:
Now stop manically fussing over your cameras and start taking
pictures! Any real problems will show up in your photographs, not
in extremely sensitive software tests on dark-frames or 500% zoom
in photo viewing utilities.
squirrel777 said:
Why are you so concerned with dead and hot pixels? Unless you
notice them in regular shooting, they won't matter. Chances are you
will get more clutter in your images from noise on the sensor than
you will from damaged pixels. Either way, most noise reduction
tools will get rid of it anyway, everything from Photoshop to Neat
Image, and whatever else you might use.

If you are that concerned with finding a dead pixel or hot pixel,
you are going to find one reguardless if it is there or not.

If you really want to find out, take a shot in the dark with the
lens cap on. Dead and hot pixels will show up there, but like I
said, it doesn't really matter if they are there or not unless you
make a big deal out of it..
Click to expand...
--
Amateur enthusiast. Equipment: 1 modern autofocus film SLR, 1
short tele zoom, 1 fast normal lens, 1 russian and 1 german TLR, 1
3.2MP point and shoot digital.
Click to expand...
 
walter23 said:
Now stop manically fussing over your cameras and start taking
pictures! Any real problems will show up in your photographs, not
in extremely sensitive software tests on dark-frames or 500% zoom
in photo viewing utilities.
Click to expand...
Keep in mind that many folks do do long exposure photography of dark scenes and that if there is a specific camera that falls outside the range of typical hot pixels that it can be a problem.

I personally don't manically fuss over my camrea (never done a focus or hot pixel test) but I do deal with hot pixels on a weekly basis.

Al
 
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