I'm reading lens reviews and I have encountered the term 'centering quality' a few times (e.g. http://www.photozone.de/sony_nex/720-sony50f18nex?start=1). What does this term mean? What are the ...
After reading this answer for another post: I don't mind the vignetting as it actually improves the look of portraits however if you're doing astrophotography what's the point in a lens that's ...