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50mm f/4 Shift C Lens
English Instructions
Namesof Parts
1) Shift Control Knob
2) Shift Scale
3) Shift Index 4) Shift Limit Window
5)
Aperture Ring
6) Focusing Ring
7) Distance Scale 8) Depth-of-Field Scale
9) Alignment Dot 10) Exposure Meter Connecting Ring
11) Exposure Meter Coupler 12) Stop-down Metering Index
Specifications
Construction 10 elements in 8 groups
Angle of View 70˚
Aperture Range f/4 – f/32
Aperture Control Manual
Minimum Focusing Distance 45 cm / 1.5 ft
Maximum Shift 16 mm vert. / 13mm hor.
Shift Direction Can be shifted in any
Image Circle Diameter 97 mm
Filter Size 77 mm
Lens Hood None
Dimensions 105.5 mm long x 80 mm diameter
Weight 705 g
Perspective Control
When photographing a tall building looking up from a low angle, the distances from the top and
bottom of the building to the lens are different. This results an apparent distortion, referred to as
converging lines. In this example, the sides of the building converge toward the top, see Fig. 1-A.
Conversely, when photographing from a high angle looking down, the sides of the building converge toward
the bottom.
In order to correct for converging lines, do not tilt the camera upward or downward. Keep the film plane
parallel to the subject with the camera back perpendicular t o the ground.
Eliminating Reflections
When photographing a reflecting surface directly from the front, a reflection of the camera will
appear in the photograph, see Fig. 2-A. To prevent the reflection, move the came sideways slightly
and shift the lens; the subject can then be photographed as desired, without the reflection of the
camera, see Fig. 2-B.
Even in the above circumstances, the same rule applies for the prevention of apparent distortion.
That is, the film plane must remain parallel to the subject in order to eliminate converging lines.
Moreover, the camera will have to be no closer than a fixed distance from the subject, the actual
distance varies with the size of the subject.
Panoramic Photography
Panoramic photographs are easily taken with a shift lens, see Figs 3-A and 3-B, below.
Firstly, mount the camera on a tripod and set the lens for a maximum horizontal shift of 13mm.
After the initial exposure, rotate the lens 180˚ and without changing the camera’s position take
the second photograph.
The two negatives will produce prints which, when jointed together, will form a single
panoramic photograph composed of two perfectly matching parts. Vertical panoramic images
are also possible.
Eliminating Obstructions
Obstructions such as trees and telephone poles which are relatively close to the camera and
appear at the edge of the frame can be eliminated by shifting lens and rot ating the camera on its
axis.
For example, an obstruction appears at the r ight edge of the frame, see Fig. 4-A, so the lens is
shifted to the right and the camera is then rotated to the left until the obstruction is eliminated, s e e
Fig. 4-B.
Precautions
Do not attempt to mount the camera with the shift lens on a tripod head that is greater
than 5cm (2 in.) in length from the tripod screw to the front edge of t he head. This is t o
prevent the Shift Control Knob from striking the tripod head when the lens is rotated.
Because of their extra thickness, there may be slight vignetting when using polarizing filters at
the maximum shift position of 16mm. At smaller shifts, and with ordinary filters used one
at a time, no vignetting will be evident.
Because it would not be practical to design a lens hood which would not cause
vignetting when shifting the lens, a hood is not available from the manufacturer.
However, the Sun Shield, an optional accessory for the Mamiya RB67, may be used to
eliminate stray light from entering the lens, see Fig. 5.
Attaching and Removing the Lens
While aligning the Alignment Dots of the camera body and lens barrel, insert the lens into the
camera body, and then twist lens clockwise until it clicks and locks intoplace. If t he l en s is held
by any part other than the Alignment Dot, the lens may rotate, preventing the lens from
mounting properly.
To remove the lens, grasp it by the part marked by the Alignment Dot, and while depressing the
LensRelease Button, twist the lens counterclockwise until it stops.
Focusing
Focusing can be done before or after shifting the lens, and be sure to focus att he maximum
aperture of f/4.
The rangefinder spot or micro focusing screens, No. 1, No. 4, and No.5, will darken when the lens is
shifted, so the best screens to use with this lens are the No. 2 Matte and the No. 3 Checker.
The latter is especially suitable as it offers perpendicular and parallel lines as reference points.
When rotating the Shift Control Knob, the visible field of view will change in accordance with the
movement of the lens. While observing this change in t he viewfinder, reposition the camera for the
desired composition.
When shifting the lens, stop down the lens as much as possible. When making large shifts, the
following apertures are recommended: Infinity: f/16 to f/22 – Close-ups: f/22 to f/32.
Shifting the Lens
When the Shift Control Knob is rotated, the lens itself moves parallel to the film plane. Additionally,
the lens can be rotated 360˚, and has click-stops at 30˚intervals. The lens can also be used
between click stops.
Since the negative area of the M645 is a rectangle (41.5x 56mmJ, the extent to which the lens can
be shifted will change each time the lens is rotated.
When the Central Index Mark of the lens, located beneath the Shift Limit Window, is uppermost or
lowermost, the lens will move horizontallywith a maximum shift of 13mm.
The maximum shift possible at each 30˚ click is indicated by a color •coded numeral appearing in
the Shift LimitWindow. This numeral indicates the maximum shift inmillimeters, and its color
matches that of its position on the Shift Scale. To avoidvignetting, the appropriate color on the
Shift Scale should not be moved beyond the Shift Index.
Exposure Determination
For a correct exposure when using an AE finder, stopped-down metering must be used.
First, make sure that the lens is coupled to the exposure meter by rotating the Exposure Meter
Coupler Ring of the lens until the Meter Coupler engages with the Coupling Pin of the finder, as
shown in the above image.
Next, rotate the Exposure Meter Connecting Ring until the Stopped-down Metering Index appearing
on the ring is aligned with the Central Index Mark of the lens. There is a click stop at this position. Be
sure to set Exposure Meter Connecting Ring to this position.
As the lens is shifted, there is a disparity in the amount of light reaching the corners and center of
the frame. Because of this disparity, it may be necessary to increase the exposure by up to one stop,
even when using a finder with a built-in meter.
The extent to which the exposure should be compensated when shifting the lens depends on such
factors as the amount of shift, the contrast of the subject, and the desired effect. Consequently,
experience is required for exposure determination and bracketing at +1/2 stop and 1 stop is
recommended.
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