Zeiss ZM 85mm f/4 Tele-Tessar T*
Since any lens of 75/85/90mm focal length is difficult to focus accurately and consistently on a rangefinder like the Leica M9, the f/4 maximum aperture is less of a real-world limitation that it might seem, at least for many types of photography.
Taking the relatively low price into account, the 85/4 might be a great choice for a compact kit where telephoto capability is needed.
The near-zero distortion and very high imaging quality make it eminently suitable for true-to-life imagery.
Like all lenses over 50mm, the key challenge on a rangefinder like the Leica M9 will be accurate focus and framing, just as with the Leica 75mm f/2 APO-Summicron-M. In essence, perfect 20/20 vision is needed, along with perfect rangefinder focus adjustment. Leica M9/M7/M8 users should consider the Viewfinder Magnifier 1.4X for use with 75/85/90mm lenses.
Very high sharpness right at ƒ/4. See review coverage in Guide to Leica.
Per Zeiss. See the datasheet.
|Aperture scale:||f/4 - f/22 in 1/3 steps
10 aperture blades
|Focusing range:||0.9m - infinity|
|Angular field, diag./horiz./vert||29/25/17 °|
|Coverage at close range:||32 cm x 21 cm|
|Image ratio at close range:||1:9|
|Number of elements/groups:||5 elements in 3 groups|
|Filter thread:||M 43 x 0.75|
|Dimensions (with caps):||ø 54 mm, length 95 mm|
A faint trace of pincushion distortion is all there is, and it’s all but identical to the ZM 85mm f/2 Sonnar.
This is effectively zero distortion for any practical purpose, and much less distortion than the Leica offerings in the 75mm - 90mm range.