Re: "Beamsplitter" & reflected vs. incident Message-ID: <960823164806.ZM9583@xxx>

[P3D William Carter <wc@xxxxxxxxxxxxxxxxxxx> To: photo-3d@xxxxxxxxxxxxxxx]

Dr. George writes:

>An incident reading in location A must be the same as a reflected reading off a "gray card" in the same location. 

I want to apostrophize this error, not because of the ongoing catachresis, but because it is both prima facie and exoteric. 

Imagine a grey card, facing your camera. The sun is directly to your right, or overhead. It is illuminating only an edge of the card. Can you expect to get a usefull reflected reading off this card? Well, I mean for anything but a flat slab.

An incident light meter is particularily usefull in complex lighting situations. Here a 3-dimentional subject may be reflecting light from several ANGLES OF INCIDENCE from a variety of sources. If you are shooting a scene lit with a key, fill, kicker, obie etc., a grey card reading, unlike the incident meter, can't register predictable exposures.




--
wc@xxxxxxxxxxxx
37deg 39.09'N x 122deg 29.56'W x 90'MLLW 





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