Uh oh, what's that on my lens?? purple blemishes on outer element

[dangermouse]

So at xmas I spent all my money and some on a canon 17-40L to put on my 300D. Everything was fine, used it a bit in the darker weather and got some nice shots (well, for me!!) but it has not been out of the bag until May. Then it has these purple-ish blemishs on the outer front element. Gentle cleaning has not removed them.

They have not got any worse since then and they don't seem to be significant enough to show up on the pictures but what are they and how can I get rid of them??

The camera is stored in the bag in a cupboard away from radiators and moisture but without any kid of protective filter. I'm pretty sure I never got it wet.

Thanks,

[Dirk]

Hi,

All lenses have a kind of coating to prevent sunlight from coming in, it kinda looks like a purple glaze and it is normal to stay on if there are no spots to be seen on sny picture . It could wll be that if it only appears in darker pictures that it is a white balance issue or an camera error.

Can you make a picture of what you mean? - that will certainly help to narrow it down

[dangermouse]

Thanks, I got some cleaning stuff and tried hard to overcome my fear of causing more damage than doing good. The good news is that the marks appear to have gone - to the naked eye. However, if I mist the glass with my breath ten they reappear, only to disappear again as the mist evapourates.

I'm much happier now, but just intrigued!!

With thanks,

DM

[Dirk]

hope that you used a lens spray and not spectacle spray or a mulit cleaner like glassex..