Specifications

17
B. There is an apparent zone of sharpness, both in front and back of
the focused subject, which is known as the depth of field. The depth
of field scale shows the zone of apparent sharpness at any lens open-
ing or distance and can be utilized for quickly and simply ascertain-
ing the depth of field. The depth of field scale is next to the distance
scales and is made up of identical pairs of apertures on both sides of
the green-colored distance index. These identical pairs of apertures
indicate the distance that will be in focus at these lens openings. For
example, if the 75mm lens is focused at a distance of 3m it can be
seen from the depth of field scale that the zone will extend from
about 1.96 to 6.80 meters (6ft to 22ft), when a lens opening of F22 is
used. Please refer to the Depth of Field Tables.
17. Focusing Adjustments
The lens is focused on the subject, by rotating the focusing ring in
either direction, while checking the effect on the matte surface in the
center of the focusing screen.
*Various interchangeable Focusing Screen Ei types are available
optionally for the camera. Therefore, a type suitable for the photo-
graphic work planned should be chosen. (See Section 23:
Interchangeable Focusing Screens)
A. Distance scales on the Bronica lenses for the ETRSi can be used for
setting the focus on the required distance or finding the distance
actually focused. Simply rotate the focusing ring and set the required
distance opposite the green-colored index, which will adjust the lens
for the required distance.
18. Distance Scale and Depth of Field Scale
19. Infrared Photography
In infrared photography, some adjustment must be made in the focus
in order to retain sharpness on the film, because the invisible infrared
rays are longer in wave length that the visible rays used for focusing.
For infrared photography:
1. Use a R filter or equivalent with an infrared (black and white) film.
2. The red-colored line, next to the green-colored distance index, is
the infrared index.