Wayne H. asks:
<< Anyone have any idea how Pop Photo measured flare ? >>
It is in Norman Goldberg's "Camera Technology - The Dark Side of the
Lens" (Academic Press, 1992). He invented the procedure and it is
described on pages 239 to 241. It involves using a white hemispheric
dome flooded with indirect light, with the test lens inserted within the
illuminated dome. But dead center is a dark point. Flare is measured
with a fiber optic and photomultiplier and light levels read on an
oscilloscope. The test compares readings off the black center versus
readings when a white object is placed in front of that black center.
Lens flare prevents the image of the black center from being truely
black, thus the "percentage flare" reported in the lens tests.
The same book describes all the other tests Goldberg devised for Popular
Photography's testing lab in the 1970-1980s.
Gary Reese
Las Vegas, NV
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