Thank you so much for all your opinions. I wasn't expecting so many posts! I suppose it all depends on the conditions at the time of taking the shot. I just got so used to having the UV filter on all the time that I never considered taking it off, especially as I use rangefinders, so I'd never miss a shot due to forgetting to take the lens cap off! For landscapes on a tripod, I'll take the filter off for the shot in future and see if I can spot any difference.