DA star 50-135
dario.bonazza at virgilio.it
Wed Dec 4 11:00:10 EST 2013
>Just take a photo of a flat surface (the classic brick wall test, for
>example) perpendicular to the camera/lens. Focus in the center with
>the lens wide open. Look at the resulting image and check that the
>left and right edges are *equally* sharp; do the same for the top vs.
And try several focusing distances, because many of those lenses perform
fine at certain distances and disalign badly at others.
Typical failures happen at intermediate focusing distances (e.g. around
1-to-3 meters, or 3-to-9 feet), while usually even poor lenses perform well
at closest distance and infinity.
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