whats this do??

[phatkid77]

did i read something about a white circle on black backround, or vice versa for measuring something............but what??

thanks

[timmciglobal]

... maybe CA? Since they are very contrasty.

I don't know.

Tim

[Norm in Fujino]

... maybe CA? Since they are very contrasty.

I don't know.

Tim

Perhaps has to do with measuring accuracy of center-weighted or evaluative exposure meters, since that kind of contrast sometimes confuses them. It was one of the faults of early (firmware 1.0) Olympus E-300s. A number of reviewers complained that the exposure was thrown off by a light object near the center of the subject.