The CCD sensor on my camera is 2272×1704 pixels, and it’s 7mm across, which means there are more than 100,000 pixels per square millimetre. My 15″ laptop screen, at a resolution of 1600×1200, has only 28px/mm^2. Both of them have exactly one broken pixel.

Laptop screen

Sensing and displaying are very different functions, but these numbers make the camera seems a lot more impressive than the screen.

I noted the laptop’s dead pixel almost immediately after starting it up for the first time. It’s in the bottom right hand corner, so I never notice it in everyday usage. After 8 months of using the camera, I’ve only just noticed its hot pixel: it only shows up on extremely dark areas, but it’s quite obvious:

Closeup of dark picture

“Hot” basically means it’s red, rather than black or white. Looking back on old pictures, it seems to have been there since I bought the camera, which is good, since that means the CCD isn’t deteriorating.

Some people send their cameras back because of problems like this, but it’s not unheard of to get back a replacement camera with even more dead pixels! The same goes for laptop screens, which manufacturers generally don’t replace unless there are more than 3 dead pixels, or one right in the centre. It’s impossible to fix the CCD so companies like Canon apparently do something to the camera’s firmware which makes it interpolate around the broken pixel. I don’t see any good reason why Canon can’t include this functionality in the end user software. It should even be possible to identify dead pixels automatically (take a pic with the lens cap on, look for red).

Extreme closeup of hot pixel

The hot pixel hasn’t really affected the surrounding pixels; it’s just the camera software making the problem bigger than it really is.

Noise

That’s a .RAW image taken with the lens cap on. Something’s going nicely wrong.

The camera, by the way, is an 8 months old Canon G3, and the laptop is a 30 month old Dell Inspiron 8000. Other than this (and the Dell having an ultra-buggy BIOS), both are highly recommended.