I have a DA 70mm ltd lens and from the day I bought it I have had a uv filter on mainly just to protect the lens. Recently I cleaned the front glass and have noticed what appears to be a bubble it can't be a scratch. I am wondering what effect this will have on my photo's. I have had this lens for six months now and think it performs well. I recently took a photo at infinity with lots of blue sky and noticed a mark in the sky - easily removed in editing. Should I return the lens under guarantee or because the lens performs well in all other situations, ignore the fault stick with the lens???
You can see the mark on right in the image attached.
Any advice on this would be greatly appreciated.
Thanks
Michael
K10D Pentax DA70mm Ltd, 50mm f1.4, Sigma 17-70mm