On 01/10/2015 20:27, NY wrote:
"dennis@home" wrote in message
eb.com...
http://www.videomaker.com/article/13...depth-of-focus


DEPTH OF FIELD - The range of object distance within which
objects are in satisfactory sharp focus, the limits being the
establishment of a circle of confusion of greatest acceptable size.
DEPTH OF FOCUS - The range through which the image plane (the
emulsion of the film) can be moved backward and forward with respect
to the camera lens such as defined under the depth of field and
circle of confusion. This term is often confused with depth of field
and vice versa.

In common English, Depth of Field is what the photographer is
interested in; it is what is in acceptable focus in front of the
lens. Depth of Focus is what only a technician is interested in; it
is what is in focus behind the rear lens element which the film or
image sensor "sees."

As illustrated very nicely by the diagram
https://encrypted-tbn2.gstatic.com/i...My4vO0bTwyLldN

that I posted earlier.

Dennis, as far as you are aware, is Whisky Dave correct to call the
"London Underground" circle-and-bar symbol on most SLRs the "depth of
focus" mark? I think the symbol marks the position of the focal plane
and that the DoFocus is, as the explanation above says, a range of
distances either side of the lens's focus point; when the lens's focus
point is the same as the focal plane, the image will be in focus on the
film/sensor.

Or is "depth of focus" ever used colloquially (and incorrectly) as a
synonym for "focal plane"?


Dave is the only person I have ever known refer to it as the DoF.
If you google "depth of focus" you won't find any images with it either.