That's a brilliant render you've done there Mark. Very realistic. I'm starting to wonder if my over-simplistic model is the problem rather than the refraction. It's just a lathed vertex object with 64 vertices for the circle. I have a glass very similar to it beside me funnily enough. :) All I know is when I look at it at the same angle as my render the refraction is minimal. Maybe I need to increase the fresnel effect to make it look more like the real glass. I agree that the presets produce great effects, but as I said it could be my lack of modelling skills that's the culprit here. I'll stick with it for now though and add more fresnel, then post it again a bit later. Thanks also for the advice about render settings. My laptop is a couple of years old and was pretty average when I bought it, so I'd say 5 minutes for me is about right. Last time I just used the high quality preset and added light through transparency to it and it took 7 minutes, so I'll probably stay with that now. Thanks again.

Darren