The Focal Length Selection Ring Has an Accurate Feeling
A somewhat small lens; almost identical in size as the prior 28-35-50 Tri-Elmar. The methods that let Leica keep the lens small was to limit the maximum aperture size to f/4 and to make a special combined lens hood and filter holder due to the front element protruding beyond the front side of the actual lens housing so they installed a bright red ring, saying, don't put me face down on the table or you're going to have made a costly mistake. As the included lens cap overlays the front side of the included special lens shade, there's fundamentally no cause to ever take the shade off allowing the red ring to forever remain hidden.
The focal length selection ring has an accurate feeling; and it's much better than the one the original Tri-Elmar. This appears to be due to a simpler link device for the frame line selector and focus coupling is needed in this new fabrication.
Optically, this new lens employs a pair of aspherical elements, and the internal focusing employs floating lens elements. For the depth of field scales there are engravings for each focal length of the lens, and the focusing device and aperture ring and have the unrivaled Leica silkiness that photographers and finely made equipment lovers will savour.
This Tri-Elmar is a true zoom lens and and can be used to shoot at virtually any focal length, and not limited to the 16-18-21mm markings. This is simple enough to discover for yourself. Way cool, particularly when used in conjunction with the Wide Angle Finder M that additionally allows in between settings.
Revised "6-bit" coding has been applied to this lens, allowing the digital M camera to optically read this information thus identify the particular lens being employed. The camera may then (alternatively) utilize a "final stage" software correction for vignetting
(for RAW images no changes are made and only the lens being utilized is
Jan 28, 2011