The term "zone focusing" dates to the early 1920s to 1930s when miniature format cameras (6x6, 35mm, etc ...) could be efficiently focused by using the depth of field rather than by scale and measurement, or by evaluating sharpness on a ground glass, due to their great depth of field compared to larger format cameras of an earlier time. Zone focus markings are touted—essentially color-coded aperture and distance settings, you set the aperture and then turn the focus to point to the same color distance on the scale—in my 1938 Berning Robot II brochure as a feature of the Zeiss and Schneider lenses available for the camera. I believe the Rolleiflex TLRs of the late 1920s were amongst the very first cameras to have DoF scales engraved on the focusing knob surround allowing effective zone focusing for when the reflex viewfinder was too dim or too slow to be effective.
> ... You needed to do it a lot more with a > rangefinder because you couldn't focus it fast enough to get the shot. ... Zone focusing was not some speedy alternative for haplessly slow rangefinder camera focusing. It existed before cameras had rangefinders. It was/is the FASTEST way to focus a camera when speed is essential—far faster and more reliable than ANY scale, rangefinder, SLR, or autofocus distance measurement system when absolute critical focus is not necessary. G -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
