Buying a new camera? Always check the sensor for faults!

[Paul Engen]

I've now bought two cameras from Canon (Powershot A95 and Eos 350D/XT). They bouth had faults on the sensors, and turns of course out as faults in the picture. When buying a new camera, you should all check the sensor for faults. It is easy:

Put the camera in manual mode and make a shot with the lens cap on (or in a completely dark room) on all ISO values. Then you will find the dead pixels looking at the picture at a 100 % magnification. (If you do it with your computer in a dark room it's easier to spot the faults.)

You should also do several shots of a evenly coloured surface (e.g. a white smooth paper) whith different exposure times giving you everything from clear white to dark grey. Then you will find the strange coloured spots (which I have found - even using short shutter speeds) and the darker rings which surrounds the dead pixels.

Turn the camera back if you find the fault! If this is too late, demand that the fault is fixed! My point is that if you don't, the camera makers will continue to sell us camaras with fault on the sensors. Consumer demands will eventually force them to fix the problem before they ship them out, or fix the problem in the first place (research that address this problem in the production stage).

[etaf]

http://webpages.charter.net/bbiggers/DCExperiments/html/body_hot_pixels.html

[InskiP]

I tried this on my 20D. I shot pics w/ both the lens cap on and a white sheet of paper and didn't see anything but a solid black, white or gray surface. No odd pixels, if I did it correctly... Would this test work to check if your sensor is dirty? How do you know if your sensor is dirty, what does it look like?

[crc_408]

I just took shots with the lens cap on in ISO 100-1600 on my 20D that I just received today :D. Used my 17-40L lens. Looked at each picusing the EOSViewerUtility at 100% and didn't see anything.

[Drk Orange]

I found a free program when I first bought my 300D that would process an image taken with the lenscap on and count the hot pixels as well as taking a note of those that were a higher value than, say, 20% brightness. (I think that's the way it goes) It would provide a summary of these so you could compare your CCD as your camera aged.

If anybody is interested, I'll try to chase it up, I have it on this computer *somewhere*.

[InskiP]

Actually, I just looked at the pics I took w/ lens cap on in DPP at 100%. I did see some tiny pinpoints of red light. What is this? Is it a problem? This camera is brand new...

[InskiP]

I should note that this was only visiable at ISO 1600. Is this just the typical noise you get at this speed, or the dead, hot, problem pixels mentioned above?

[tim]

Don't worry about noise if it's only at ISO1600, you won't probably notice it.

[l bo]

Great! Thanks for bumming me out :( I took this test with lens cap on.

At 1600 iso with 30" exposure there were all kinds of stuff, no biggie.

At the other end of the spectrum, 100 ISO, there are 5 or 6 spots that show at all speeds 1/5 second and slower.

So does this mean out of 6,300,000 pixels 5 or 6 are bad??????

I am not going to worry about it, but I am bitter to find a flaw with it.

[Merle]

Thank you Paul,

For posting that information. I learned some good stuff today.;) :) :D

Good Shooting to Ya !!
Merle

[Raj]

This is a sticky mentioning something to check when you make a new (camera) purchase

http://photography-on-the.net/forum/showthread.php?t=58493