Operation Manual

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BRIGHT-LINE VIEW- AND RANGEFINDER
The Leica M9’s bright-line view and range nder is not
only a very high-quality, large, brilliant and bright view-
nder, it is also a highly accurate range nder coupled
to the lens. It has an enlargement factor of 0.68x.
The size of the bright-line frame is optimized for the
full format of the Leica M9 and thus corresponds
ap proximately to the sensor size of 24x36mm
1
with
a distance setting of 1m. The bright-line frames are
linked to the distance setting in such a way that paral-
lax error - the misalignment between the lens and the
viewnder axis - is automatically compensated. The
bright-line image and the picture are practically iden-
tical over the entire distance setting range of 0.7m
to ∞. Practically identical means that at distances of
less than 1m the sensor records slightly less than is
displayed by the inner edges of the bright-line frames
and records slightly more at longer distances (see
adjacent graphs). These slight variations, which are
rarely signicant in practice, are due to the operating
principle:
Bright-line frames on a viewnder camera must be
adjusted to the angle of view of the relevant lens focal
lengths. However, the nominal angles 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 innity
(and the extension is correspondingly larger), the
actual image angle is also lower and the lens records
less of the subject. In addition, the image angle dier-
ences are greater at longer focal lengths as a result of
the greater extension.
All pictures and bright-line frame positions relate to 50mm focal
length
A Bright-line frame
B Actual image eld
Set to 0.7m: The sensor records approx. one frame width less.
Set to 1m: The sensor records exactly the image eld dis-
played by the inner edges of the bright-line frame.
Set to innity:
The sensor records approx. 1 (vertically) / 4 (hori-
zontally) frame width(s) more.
1
The exact format is 23.9 x 35.8mm, corresponding to the usable
format of analog Leica M models.
A
B