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4X Objective Lens Test Comparison - Part 1
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cactuspic



Joined: 26 Dec 2006
Posts: 432
Location: Dallas, TX

PostPosted: Wed Dec 20, 2017 5:56 pm    Post subject: Reply with quote

Robert, thanks for all your care and effort. The tests really help those of us on a limited budget more efficiently buy equipment that makes a difference in our photography. Great work.

Irwin
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ray_parkhurst



Joined: 20 Nov 2010
Posts: 1634
Location: Santa Clara, CA, USA

PostPosted: Wed Dec 20, 2017 6:03 pm    Post subject: Reply with quote

Robert...this may have been mentioned, but have you considered doing a 3D rendering of the stacks in order to compare the field flatness of these objectives? I did that a while back and it was useful. I used a flat surface (your wafer will be much better) and the rendering gave me a good indication of the shape of the focused surface. As I remember, one of the objectives I tested had decent sharpness at the corners, but the field un-flatness was so severe that it took an inordinate number of shots to get the whole surface in focus. So although it "could" produce a sharp image of the whole surface, it was not practical. A true plan objective could do the same job in just a few shots.
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