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Lens selection
Each MP 4+ lens is designed for
reproductions within a specific range.
This chart shows the approximate
ranges; see the Appendix Chapter for
more details.
Lens
Minimum
135mm
10%
105mm
20%
75mm
1.5x
50mm
1.5x
35mm
5 x
17mm
10x
*
Use one or two macro extensions
for additional magnification.
Sizing and focusing
General rule: To increase the size of the
image on the ground glass, lower the
camera and lengthen the bellows (27).
To decrease the size of the image, raise
the camera and shorten the bellows
(28).
Maximum *
Reductions: First, adjust the camera
1.2x
height to get the approximate image
size required. Then, adjust the bellows
1.5x
for sharp focus. Magnifications: First,
3x
adjust the bellows to get the approxi-
5x
mate image size required. Then adjust
the camera height to attain sharp focus.
7.5x
Camera column scale: When the
20x
column scale is read at the point
indicated (29), it represents the film
plane to baseboard distance.
Bellows scale: The scale on the left
focusing column represents the bellows
extension, when it is read at the point
indicated (30).
These scales can be used in conjunc-
tion with the tables in the Appendix
Chapter to set the camera for specific
reproduction ratios.
Note: If the exact reproduction ratio
must be documented, place a ruler on
the baseboard and photograph it with
the original subject (31). Be sure the
ruler is in the same plane as the original
subject.
Operations
6
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