Tested my 55-200mm is this acceptable?

Started Dec 9, 2019 | Discussions thread
bemeta Regular Member • Posts: 353
Re: Tested my 55-200mm is this acceptable?

It certainly is not the best test, but it is easily executed.

If this test is 'good enough' is something I just would not be able to say. To improve it somewhat I suppose the diagonality can be limited by picking a suitable target (a wall perpendicular to the optical axis for example), and the non-flatness of the target is probably relatively small at large distances (the distance should be as close to infinity as reasonably possible I'd say). I suppose the fact that one corner is substantially different from the other corners, might at least indicate something might not be right, and further testing could be sensible.

Factually I have no idea what the probability of detection is, nor what the false positive rate would be. Of course that might be such that it is unwise to use this test in any case.

Anyway, I would advise Inpuressa to retest it, maybe on a target at a larger distance, and if it is consistently uneven in the corners at 55mm, to have it tested/replaced/repaired if this issue would otherwise keep nagging him/her.

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