Ko.Fe.
Lenses 35/21 Gears 46/20
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As for micro scratches and the likes degrading image quality. I suppose it may be quantifiable. But whether or not it is remotely noticeable, may be another matter. Lensrentals did a blog post some time ago giving an idea of how badly a front element can be damaged and still produce usable images. Of course you never want it to go to that extreme. 🙂....
What else you would expect from rent for profit? "The lens is trash, but we still charge you".