"x mark" in dslr images

That is a dead pixel on the camera sensor...

If you google how to fix a dead pixel there are a few ways to try! Unless its brand new then see if shop can swap it for you.

Graham

Thanks Graham, I've been googling and it seems there's a variety of pixel defects - apparently a stuck pixel appears as a cross and might disappear over time, whereas the methods suggested for fixing dead pixels sound like they might do more harm than good... I'm going to go through my images to see how long the problem has persisted.

@Dave, yes here's how it appears really magnified in Photo viewer:



Thanks guys.

That's a bright hot pixel after the jpeg algorithms got to it. They are probably trying to smooth is out a little so it wont be as obvious, which would probably work for daytime images. If you look at the raw image I'd bet it's a single pixel.

Removing it automatically at the jpeg level is probably going to be tricky since the 8 pixels around it will be calculated based on their surrounding pixels. But by shooting in raw you can apply a dark frame to remove it before further processing.

I thought canon had something in the firmware now to do hot pixel mapping in the background, that might not be in the 1100D, but have a look through the manual there might be some option in the sensor cleaning section that can help you.