Small 'smudge' on IXUS850 screen and prints

[Smuff62]

I've noticed a small circular smudge mark on my LCD and prints. I can't see anything on the lens, even using a magnifying glass. If I use the zoom, the smudge gets smaller but more vivid.

Could this be damaged pixels? Any ideas gratefully accepted.

[Jon]

First, are you using digital zoom? Second, by "use the zoom", do you mean to zoom out (wide) or in (tele). It really does, though, sound like it is on the lens, possibly an internal surface. Can you post an example?

[Smuff62]

Thanks Jon,

Here are a couple of shots I've just taken of a plain yellow wall. The first is without zoom, the second, using the digital zoom to go in close.

[blam]

looks like dust

[Jon]

First - go into your setup and turn OFF the digital zoom. Then forget you ever had it. All it does is throw away pixels around the edge of your picture and split up the ones in the center. 4x digital zoom on an 8 MP camera uses about 0.5 MP of your sensor, and pretends each one of those pixels is really 16. You can do the same thing yourself in post-processing and get at least as good results. But according to the EXIF data, you didn't use digital zoom on that, just real optical zoom which uses your entire sensor.

That second shot does look like dust, but could you shoot a uniformly-lit area rather than something with as variable lighting as that wall has? It makes it easier for us to tell what's there.