120
BRIGHT LINE VIEW AND RANGE FINDER
The Leica M Monochrom’s bright line view and range
finder is not only a very high-quality, large, brilliant and
bright viewfinder, it is also an extremely accurate range
finder coupled to the lens. It has a magnification factor
of 0.68x.
The size of the bright line frame is matched to the
initial format of the Leica M Monochrom and thus
corresponds to a sensor size of approximately 24 x
36mm
1
at a distance setting of 1m. The bright line
frame is linked to the distance setting to ensure
that parallax - the offset between the lens and the
viewfinder axis - is automatically compensated. The
bright line frame and the picture image are largely
congruent over the entire distance range from 0.7m
to ∞. Largely means that at distances of below 1m the
sensor detects slightly less than shown by the inner
edges of the bright line frame, and slightly more at
greater distances (see adjacent diagram). These slight
variations, which are hardly ever critical in practice, are
due to the operating principle.
1
The exact format is 23.9 x 35.8mm, thus corresponding to the
usable format of analog Leica M models.
Bright line frames on a viewfinder camera must be
matched to the angle of view the relevant lens focal
lengths. However, the nominal angle of view change
slightly when focusing due to the changing extension,
i.e. the distance between the optical system and the
sensor plane. If the set distance is less than infinity
(and the extension correspondingly greater), the actual
angle of view is smaller - the lens captures less of the
subject. In addition, the differences in the angle of view
tend to be greater at longer focal lengths, as a result of
the greater extension.
If lenses with focal lengths of 28 mm (Elmarit from
serial number 2 411 001 onwards), 35, 50, 75, 90 and
135mm are used, the associated bright line frame is
automatically displayed in the combinations 28+90mm,
35+135mm, 50+75mm.
In the middle of the viewfinder image is the rectangular
distance metering field, which is brighter than the
surrounding image field. All lenses from 16 to 135mm
focal length are linked to the range finder when
attached to the Leica M Monochrom.
If the exposure meter is turned on, the exposure meter
LEDs and the flash symbol LED appear at the lower
edge of the viewfinder image.
For more details about setting the distance and
exposure metering, and on flash mode, refer to the
relevant sections on pages 122/123/130.
IMAGE FIELD SELECTOR
The image field selector (1.8) expands the possibilities
of the Leica M Monochrom viewfinder. This built in
universal viewfinder allows you to activate bright
lines at any time, which do not belong to the lens
currently being used. You can then see immediately
if, for compositional reasons, it would be better to
photograph the relevant subject using a different focal
length.
If the lever is rotated outwards, i.e. away from the lens,
the frames for 35 and 135mm focal length are shown.
If the lever is moved to its vertical central position, the
frames for the focal lengths 50 and 75mm appear.
If the lever is rotated inwards, i.e. towards the lens, the
frames for 28 and 90mm focal length are shown.
