I just purchased an EF 100mm Macro USM (non-L) from a member on FredMiranda. The lens has very tiny pin-point flaws on both the front and rear elements, visible when a flashlight is pointed at them. They don't look like scratches, they are too small and superficial to be scratches- and they might only affect the coatings and not the glass. There are about half a dozen, and they are midway between the center and the edge on both elements.
My question is, will these affect the image, and if so, how can I test for it? The seller has agreed to take it back for a full refund but I don't want to return it unless I really see an adverse effect. Can someone please guide me on what to look for?
Thanks in advance.