>>4291617>>4291623As a massive gearfag, it's my opinion that unless your technique is perfect it's hard to tell between non-broken lenses that are actual lenses (ie not disposables or lomos or p&s zooms, etc), at least for sharpness.
And that also at the same time, if your shooting technique is perfect then it will be pretty irrelevant because the photo will be acceptably sharp for most uses anyway, even with a poor lense.
>howeverThings like off centre sharpness/corner smearing and ca/colour fringing/purple flare will give the game away for low quality optics.
Pic related I shot a whole roll with this low-breed smegron 28mm on sharp colour film for exactly that reason, to see how much I'd really notice. It's just never sharp in the corners even at f/16, where my Nikkor in the post above ^^^ is sharp all over the frame even at wide apertures.
If I took the same photos with both lenses I wouldn't have an issue with the results from either, but even a layman would pick the better lens if you put them side by side.