Leica APO-VARIO-ELMARIT-SL 1:2.8-4/90-280 Notice D'utilisation page 20

TAKING PHOTOGRAPHS WITH AUTOMATIC EXPOSURE AND BY MANUALLY
EN
SETTING SHUTTER SPEED AND APERTURE
The Leica Apo-Vario-Elmarit-SL 1:2,8-4/90-280mm has a variable shutter speed, i.e. the effective
aperture opening depends on the focal length set. For example, if the aperture value of 2.8 is set at
90mm, the aperture corresponds to the value displayed. At longer focal lengths, the actual opening
reduces and, finally, at 280mm the second value 4 specified in the name of the lens applies. Thanks
to light measuring by the lens, however, the right amount of light is always measured in all exposure
modes.
However, to prevent incorrect exposure, the desired shot composition (focal length choice) for the
subsequent shot must be identified before the measured value is saved or the time/aperture
combination is changed. This also applies to flash mode with manual setting of the output or
computer control on the flash unit. In both cases, the aperture setting on the flash unit must always
correspond to the actual aperture opening. However, when a system flash unit is used and the TTL
flash exposure control, the actual aperture opening is automatically transmitted so that the correct
exposure is always guaranteed.
LENS HOOD
The Leica Vario-Elmarit-SL 1:2.8-4/90-280mm is supplied with a lens hood ideally matched to
1
optical paths. Thanks to its symmetrical bayonet it can be fitted quickly and simply, or vice versa for
space-saving storage. In both cases, when the lens cover is removed, it is initially fitted so that one of
the index points on the lens hood is precisely opposite the index point on the front mount of the
2b
lens . In this alignment, the lens hood is fitted and turned by approx. 30° until it clearly engages,
1a
audibly and noticeably. For as long as the camera is being carried and used ready for photography,
the lens hood should alway remain fitted. It provides effective protection against contrast-reducing
stray light and also against damage and soiling of the front lens, e.g. from accidental fingerprints.
16