Doug Kerr
Well-known member
I never use the Zone System for exposure planning, but of course my work on exposure metering brings me into contact with it here and there.
I am mystified by the following.
Conceptually, the full Zone System range comprises 11 zones, identified as 0 through X. Often only zones 1-IX are actually considered.
Purportedly, the zones are at intervals of one stop (or a 2:1 difference in exposure).
Often Zone V is spoken of as sort of the "anchor" of the system, intended to receive objects of a "mid gray" reflectance, often thought to be a reflectance of perhaps 18% (and accordingly, the photometric exposure for such items should be, in a digital context where this has clear meaning, something like 18% of saturation).
But if we assume that the top of zone X would correspond to saturation, then the middle of zone V (5.5 stops down from that) would have a reflectance implication of about 2.2%, not close at all to 18%.
If we think of a "zone V placement" as receiving a photometric exposure of 18% of saturation, then the brightest object we could accommodate (it would get a photometric exposure a little less than saturation) be thought of as ending up in zone VII.
What am I missing here?
Thanks.
Best regards,
Doug
I am mystified by the following.
Conceptually, the full Zone System range comprises 11 zones, identified as 0 through X. Often only zones 1-IX are actually considered.
Purportedly, the zones are at intervals of one stop (or a 2:1 difference in exposure).
Often Zone V is spoken of as sort of the "anchor" of the system, intended to receive objects of a "mid gray" reflectance, often thought to be a reflectance of perhaps 18% (and accordingly, the photometric exposure for such items should be, in a digital context where this has clear meaning, something like 18% of saturation).
But if we assume that the top of zone X would correspond to saturation, then the middle of zone V (5.5 stops down from that) would have a reflectance implication of about 2.2%, not close at all to 18%.
If we think of a "zone V placement" as receiving a photometric exposure of 18% of saturation, then the brightest object we could accommodate (it would get a photometric exposure a little less than saturation) be thought of as ending up in zone VII.
What am I missing here?
Thanks.
Best regards,
Doug