View Full Version : Do i have a hot or dead pixel problem?


Felix Theissen
January 28th, 2007, 02:56 PM
Hi i tested my A1 with slow shutter and high gain and could see a few hot
pixels.
Is it normal to find a few (5 or 6) of them with very high gain? I am little bit concerned
because i have no high def monitor but with high gain and slow shutter
i could see them on my macbook in the little imovie window.
So i don´t know, if i could see them with lower gain seetings on hi def.
Because i am in the two week return time, does anybody know is this a
normal behaviour or should i ask for replacement?
They are in the lower left corner and in the middle and in the upper middle.
Maybe someone can take a look at the examples:

The first is with lens cap on. (uploaded)

http://www.felixtheissen.com/test/Canon_XH-A1.mov

The second is with lens cap of. (will be uploaded fully in 25 min)

http://www.felixtheissen.com/test/Canon_XH-A1_2.mov

Felix

Bill Pryor
January 28th, 2007, 05:07 PM
Can you put an arrow or something to what you're seeing. I can't see anything that looks like a dead pixel.

Felix Theissen
January 28th, 2007, 05:39 PM
Can you put an arrow or something to what you're seeing. I can't see anything that looks like a dead pixel.

I don´t know how to mark the movie, that´s why i marked stills, but if you look
afterwards at the movie (especially the first one) you can see them.
I marked 3 hot pixels from the 6 i found.
But it occurs only with slow shutter and high gain.
(I don´t know whether this a common behaviour?)

Thank you for looking at it:

http://www.felixtheissen.com/test/Hot1.tiff

http://www.felixtheissen.com/test/Hot2.tiff

http://www.felixtheissen.com/test/Hot3.tiff

Felix

Felix Theissen
January 29th, 2007, 05:34 AM
Ok, maybe i should ask more directly. Is this a normal behaviour of camcorder ccd´s to
show hot pixels (i defintetly see more as 6 of them) under certain circumstances
like high gain cobined with shutter speeds lower 1/12 s and i should not worry
about that. Or are this weak points of the ccd in the future.
Why i am asking here in the forum is: i live in germany which is still a kind
of a service desert. My contact to the canon phone support
in Germany was waiting in the line (paying). I still have no answer.
If this problem with the hot pixels will show up in the future only on 1/6 or 1/3
shutter with high gain, then i could live with that. But could it be that these
pixels develop a stronger malfunction in the future?
I bought the camcorder for a project we maybe want to blow up to 35 mm.
Bad pixels would be more worse then.
For the next 3 day i have to consider whether to return it and/of ask for replacement.
Other than that (my concerns about these pixel and not being able to
capture with fcp directly without tape) it´s a great camcorder.
My question: are hot pixels normal?

Felix

Anthony Leong
January 29th, 2007, 07:57 AM
Sorry Felix, but I can't see anything that look like a dead pixel.

Matthew Nayman
January 29th, 2007, 08:08 AM
Hey Felix,

My camera actually does have a hot pixel. Mine is a problem cause it shows up at 6db of gain at 1/24 shutter which are fairly normal settings. Anything lower than 1/24, you can probably expect a hot pixel or two, but if you typically shoot at these speeds with high gain, you might want to contact canon. Mine is currently out having a hot-pixel issue resolved.

Philip Williams
January 29th, 2007, 08:09 AM
Some hot/stuck pixels under high gain settings are, I believe, considered acceptable. From what I've read and experienced, low shutter speeds can also factor into the equation and increase hot/stuck pixels.

I just watched the movie samples and looked at your still captures. I'd say given the massive gain and slow shutter speed used that your camera is fine. Believe me, at that level of noise when your audience asks "what's wrong with the picture", they're not going to be referring to one pixel :)

How does the image look at 1/25th shutter with 6db gain? Maybe 12db.

Felix Theissen
January 29th, 2007, 10:50 AM
Thank you for the answers. Yes, it only appears with highest gain and 1/3 or 1/6
shutter speed, so i assume the camera is ok. And i managed it now to capture
with fcp directly to disk. trick is tape must be in the camera (but you don´t have to hit record).
Just for the record i attached a 800% sceenshot of two of the hot ones.

http://www.felixtheissen.com/test/Hot4.tiff


Thank you again for answering my maybe dumb question. I am learning.
And here is a good place for finding a lot of valueable information.

Philip Williams
January 29th, 2007, 11:51 AM
Thank you for the answers. Yes, it only appears with highest gain and 1/3 or 1/6
shutter speed,...<snip>


Oh yeah, I bet some hot pixels are more likely than not to appear on any XH A1 at those settings.


Thank you again for answering my maybe dumb question. I am learning.
And here is a good place for finding a lot of valueable information.

Actually that was a pretty valid question. And yes, there's a TON of info here.

Doblac Lubicic
February 6th, 2007, 09:13 AM
Hello,
I see you are from Germany, so I write my answer in German.

Ich weiß nicht ob dein Problem sich schon gelöst hat, aber das was man auf deinem Beispielmaterial sieht, ist ganz übles Rauschen.
Ich vermute mal, dass die Kamera den Gain bis auf 36db hochgezogen hat und das ists dann vorbei mit den schönen Bildern.

MfG

sorry to the English users, but it is easier.

Felix Theissen
February 6th, 2007, 02:07 PM
Hello,
I see you are from Germany, so I write my answer in German.

Ich weiß nicht ob dein Problem sich schon gelöst hat, aber das was man auf deinem Beispielmaterial sieht, ist ganz übles Rauschen.
Ich vermute mal, dass die Kamera den Gain bis auf 36db hochgezogen hat und das ists dann vorbei mit den schönen Bildern.

MfG

sorry to the English users, but it is easier.

Danke für die Antwort. Thanks, the problem was, as i found out how to test the canon with manual mode and 6db gain i found hot pixels with slow
shutter 1/3 and 1/6 at 6 db gain (even lower) and then you see it, because the rest of the picture is mor or less clean. It became worse the longer the camera was switched on.
I was in the 14 days return time, so i am waiting for the replacement. (the
canon repair center in berlin told me to do so)
Felix