Operation is also Leica like: Similar to a two-ring zoom, the focal length is set with a separate ring that clicks into position audibly and tangibly so accidental changes are prevented. And of course, the appropriate bright-line frame is projected in the viewfinder with each focal length.
The LEICA TRI-ELMAR-M f/4.0/28-35-50 mm ASPH. is distinguished by a good to very good rendition at all three focal lengths. The use of highly-refractive glass for five of the lens elements as well as two aspherical surfaces results in a richly contrasting image with good reproduction of details even at full stop. Aberrations such as coma, vignetting, and curvature of field are small to begin with and can be virtually eliminated by stopping down to f/5.6-8.
The LEICA TRI-ELMAR-M f/4.0/28-35-50 mm ASPH. can generally be used on previous LEICA M-models.