You'll recall the scratched lens was a Takumar-A 28-80 F3.5-4.5 macro zoom. Sometime in its life it had been tossed into a kit bag without a cap or UV filter, and the front element suffered numerous small, light scratches (apparently from sharp metal edges) over half the lens... but thankfully not too near the center. I first applied a _little_ Rain-X and when dry polished with a damp tissue. No visible effect on scratches. Next I _flooded_ the front element with Rain-X and and when dry wet-polished again. The lens cleaned up fine, with scratches _perhaps_ a tiny bit less obvious now. Shooting a test series at 28mm 50mm and 80mm showed a very slight flare at F4 (my *ist-DS on manual mode would not show any F/3.5) which could be improved to "not bad" with a touch of the unsharp mask. The flare vanished at F5.6 and above, while apertures F/8 and F/11 were quite sharp enough to rescue the lens from the trash can... since currently its the only true macro lens I have. I was pleased to find no eueball-measureable barrel distortion at the 28mm position, even after I drew straight lines on the test image's vertical and horizontal elements. Conclusion: though I had not tested this lens extensively before Rain-X, it did not hurt the lens, and _may_ have helped. The lens did _not_ turn into a soft-focus portrait lens, which I was willing to risk. Note that the Z-wax suggested as a repair is not claimed by its manufacturer to fill lens scratches... it is merely a cleaner and anti- fog agent, allegedly containing a water-soluable (!) wax.
