User Guide

195

Exposure Basic Settings

Floating ISO, when using zoom lenses with variable aperture (such

as the Leica Vario-Elmarit-SL 24-90 f/2.8-4 ASPH.), ensures

correct exposure with manual exposure setting (M) or, with

aperture priority (A), shutter priority (T) and program modes (P),

also retention of the shutter speeds and aperture values set

automatically and/or manually.

Explanation:

The aperture speeds and aperture values (m) set manually with a

focal length of such a lens result in brighter or darker exposure

than intended with shorter or longer focal lengths due to the larger

or smaller aperture openings. Floating ISO automatically changes

the sensitivity, so that the desired exposure is retained with every

focal length. Although the three automatic exposure modes (A, T,

P) set the correct exposure at every focal length, they do so by

means of changed shutter speeds and/or aperture values.

Floating ISO also automatically changes the sensitivity in these

cases so that both the desired exposure and the original shutter

speed/aperture combination is retained at every focal length.

Notes:

• Maximum ISO and Maximum Exposure Time are only eﬀective when

ISO is set to Auto ISO.

• 1/f results in the slowest possible shutter speeds based on the

rule of thumb for free-handed, blur-free pictures, e.g. 1⁄100s with

a focal length of 100 mm. 1/2f is principally the same, except

that it results in twice as fast shutter speeds whenever possible,

e.g. for even more safety against blurred pictures.

• Floating ISO is not available when Auto ISO is switched on.

• Floating ISO can work only if the original ISO setting allows

scope for change, i.e.. the highest/lowest ISO setting is not

already being used. If this is the case, the Floating ISO warning

symbol is displayed.