[Leica] Lens names

[Doug Herr <Telyt@compuserve.com>]

Adam Bridge, a neophyte, asked:

>>>
When I look at the names of Leica lenses I find things like:

ELMARIT
SUMMILUX
TRI-ELMAR
ELMAR
SUMMICRON
APO-TELYT

Are these model names, or do they imply something about the optical design
of
the lens?
<<<

Adam,

In current usage it sez something about the lens' maximum aperture or focal
length:

ELMARIT = f/2.8
SUMMILUX = f/1.4
ELMAR = aperture smaller than f/2.8
TRI-ELMAR = 3 focal lengths, aperture smaller than f/2.8
SUMMICRON = f/2.0
APO-TELYT = big honkin' piece of glass.  Oops, I mean the TELYT part means
it's a long lens, 200mm or more, on in the case of the original APO-TELYT,
180mm.  The APO part means the lateral and longitudinal color aberations
are essentially nil, so if your pictures aren't sharp it's not the lens'
fault.


>>>
And, since I'm revealing massive ignorance which probably will result in
being
removed from this august list, I might as well ask: what's the deal with
"ASPH"
lenses. 
<<<

ASPH means the design incorporates at least one glass element with an
aspherical surface.  By itself that doesn't mean anything but usually if a
manufacturer goes to the trouble and expense of producing an aspherical
surface it's because the lens designer found a way to make the lens really
really good by using the aspherical surface.  In the case of a Leica ASPH,
it's the good stuff.

Doug Herr
Sacramento
http://ourworld.compuserve.com/homepages/telyt