Doug Kerr
Well-known member
The APEX system (the Additive System of Photographic Exposure), introduced in 1961 (good grief! I was only 25 years old then!) defines a system of specifying various factors involved in photographic exposure (exposure time, film sensitivity, etc.) in logarithmic form. Its main objective was to allow a photographer to work the "standard photographic exposure equation" in a form that only involved addition.
But by that time, the widespread use of exposure meters that calculated the exposure for us, and even the use of automatic exposure cameras, essentially eliminated the broad utility of this new system.
Nonetheless, it is still a useful construct in various technical areas. For example, the encoding of the metadata (often miscalled "Exif data") in several modern image filetypes is based on the APEX representation of the factors. And one of its factors (the exposure value, Ev) still has a number of uses (and a number of misuses).
My article posted on The Pumpkin, "the Additive System of Photographic Exposure", has recently been substantially revised and reissued (as Issue 10). There is no new or really changed information. The revision primarily reorganizes the presentation and hopefully makes various points clearer (or at least more precise).
It is indexed here on The Pumpkin:
Best regards,
Doug
But by that time, the widespread use of exposure meters that calculated the exposure for us, and even the use of automatic exposure cameras, essentially eliminated the broad utility of this new system.
Nonetheless, it is still a useful construct in various technical areas. For example, the encoding of the metadata (often miscalled "Exif data") in several modern image filetypes is based on the APEX representation of the factors. And one of its factors (the exposure value, Ev) still has a number of uses (and a number of misuses).
My article posted on The Pumpkin, "the Additive System of Photographic Exposure", has recently been substantially revised and reissued (as Issue 10). There is no new or really changed information. The revision primarily reorganizes the presentation and hopefully makes various points clearer (or at least more precise).
It is indexed here on The Pumpkin:
Best regards,
Doug
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