Leica SUMMARIT-S 1:2.5/120mm ASPH Instructions Manual page 19

Care tips for your lens
Dust on the outer lenses should be removed with a soft hair brush or carefully using a clean,
dry, soft cloth. Micro fiber cloths (available from specialist retailers) are ideal and can be
washed at up to 40 °C. To remove marks or fingerprints, wipe the lens with this cloth starting
in the middle and working towards the edge in a circular motion. Special cleaning cloths for
glasses should not be used as they are impregnated with chemicals that can damage the
types of glass and coatings used. Do not exert heavy pressure when wiping highly soiled lens
surfaces. Although the coating is highly abrasion resistant, it can be damaged by sand or salt
crystals. Never use acetone for cleaning.
The bayonet is given an ultra-thin film of grease in the factory to ensure that the lens can be
changed easily, gently and smoothly. In normal use, this is retained for many years even if the
bayonet is occasionally wiped with a clean cloth. If a substance that dis solves grease is used
for cleaning, the grease film must subsequently be replaced. To do this, coat the bayonet with
a tiny amount of Vaseline with a finger and spread using a clean cloth.
In addition to the type designation, every lens has its "personal" serial number. Note this
number in your documentation for security.
Dust and splashed water protection
Leica S lenses have a range of design fea tures that provide a certain amount of protection
against moisture and dust. However, they should not be continuously exposed to rain. Ensure
that neither water nor sand and dust can get into the lenses, e. g. when it is snowing or rain-
ing and on the beach.
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