Checking a lens for sharpness and quality

Do you have a sure method.
Ian

I don't test my new lenses by any other method than taking lots of shots and then seeing the results.

Sometimes a check on perhaps a newspaper page can be useful in comparing the sharpness of two lenses, but the real world photos should normally suffice.

If you want to test in a more scientific way then very precise technique is needed.

I concur with John. If I like the photos a lens produces then that's good enough for me - I only resort to any form of testing if there's an obvious problem.

I recently bought a Tamron 18-200 after reading several reviews.

In the real world the lens was producing fringing around objects, focussing slowly and needing higher ISO than a Sigma equivalent.

Suffice to say I'm not happy and it's been returned to be sorted.

So, yes John is right, loads of shots and compare, if your not happy return it for a replacement/service under warranty/refund. Not all lenses are perfect, like anything there's always the occasional duff one.