Dead pixels

[Travy]

Not really sure where to put this or what im asking..

But im 99% sure i have dead pixels in my 400D's sensor.
I have been told since finding it that its common?
And that canon wont replace it unless there are a certain dead pixel to pixel ratio

The camera was bought 31/12/06 so its under warranty..

The spots only appear under long exposures.. and also appear when you take a picture with the lens cap on.. (on purpose )
3 spots 2 white and one red. When i shot the lens cap they get brighter the longer you expose it.... Now if the lens cap is on then no light is getting in.. if it was dust it wouldnt appear would it? or get brighter?

Should i just deal with and have to process any long exposure shots getting rid of the spots? they blend in when you shrink the photo etc..


Anyone else had experience with this and had dealings with suppliers about it?

Sorry for the long ramble.
Regards
Trav.

[ozonejunkie]

G'day Trav,

I wouldn't be too concerned about this personally. My 300D that I used to own had this problem, but it was only really apparent on 1+ minute exposures.

My solution was to shoot RAW, and let photoshop handle the removal of these defects. If i recall correctly i had 4-5 white pixels, and a green one.

If you feel it is a problem, then perhaps try and research it more - it never worried me though!

Tristan

[Travy]

Hi Tristan

Mine does it on 20 seconds exposures sometimes even less if its a dark shot.

They were very obvious when i was trying to capture lightning.

I dont shoot in RAW yet .. still a beginner

[ozonejunkie]

I would check my old camera - but I have sold it sorry.

Does the 400D have a setting in custom functions to turn on long exposure noise reduction? This is specifically designed to remove this noise. It can be a pain sometimes, as it does double the exposure length - but it will get rid of these problems.

Oh - and give RAW a go - you will never be happy with JPEG ever again.

Tristan

[rooboy]

My D70s have a few hot pixels - nothing to worry about if you use long exposure noise reduction as ozonejunkie suggests. This is also called dark frame subtraction, as it 'subtracts' a dark frame (e.g. lens cap on) from the real photo, which gets rid of hot pixels, and in the case of a D70, sensor warming up in the top left corner.

As said, it doubles the exposure length - use this time to frame the next shot, as you can move the camera freely while it's doing its noise reduction.

[hart]

If you are noticing them during normal photography (ie: not shooting your lens cap) then I'd be giving Canon a hard time over it.

When i shot the lens cap they get brighter the longer you expose it.... Now if the lens cap is on then no light is getting in..

Did you have the viewfinder cover on too? Light can get in there too

Another way of analysing your sensor is to use the deadpixeltest application (google) - it can help confirm exactly how many pixels are dead or stuck, which may help you with Canon.

[rooboy]

Did you have the viewfinder cover on too? Light can get in there too

Light coming in from the viewfinder will affect the metering, but I'd be worried if it was making its way to the sensor while the mirror was raised

[hart]

On long exposures, it will make it through. The Canon instruction manual even says so - that's why the neck strap comes with a viewfinder cover.

[Travy]

Shooting the lens cap its noticable on 5 second exposure.. and very bright at 10 second exposure.

I messed around tonight doin random long exposures of nothing in particular.. and the spots are there.

I will try covering the viewfinder and shooting lens caps tomorrow.

[photoham]

If it bothers you and you don't want to edit during PP then I'd suggest sending it back to Canon for repair.

I'm reasonably sure that what Canon will do is not replace the sensor but remap the pixels for you in the camera's software. I had it done on my old G1 under warranty (at the time) and while I can't remember what the tech said I suspect that it takes data from adjacent pixels to fill in the missing data.

[B01NG]

i got the same problem with my 350d, nothing to be concerned about i'd say. It did bother me to begin with though, now, i just clone out the red/blue pixels. i also noticed that if you use noise reduction, those pixels dont appear. but then, you can only use that function when the exposure is 30 secs or more.

[Travy]

I covered the viewfinder and shot the lens cap.. still there..


here is a cropped section of the spots.. the other is the same as the white one but out to the side..

[!~DeViNe~DaRkNeSs~!]

thats real gay!

[Travy]

Camera has been sent back to canon after a phone call to repair centre..

will let you know the out come.