Leica APO-Summicron-M 90mm f/2 ASPH

Leica APO-Summicron-M 90mm f/2 ASPH

When Leica introduced this lens in 1998, it was positioned as the company's reference short telephoto for the M system, combining apochromatic correction with an aspherical surface to deliver high sharpness at full aperture rather than only when stopped down [1][2]. It replaced the earlier non-APO, non-aspherical 90mm f/2 Summicron-M, and reviewers have repeatedly described it as among the highest-performing 90mm rangefinder lenses ever produced [2]. The combination of fast f/2 speed in a moderately compact telephoto, together with Leica's typical build quality, is the main reason collectors and working photographers continue to seek it out [2].

The optical layout uses five elements in five groups with one ground aspherical surface, an unusually simple count for an apochromatic design [1][2]. The lens focuses to one meter and uses an eleven-blade diaphragm running from f/2 to f/16 with half-stop clicks, which produces delicate sunstars when stopped down [1][2]. It takes 55mm screw-in filters, a larger thread than most M lenses, and carries a built-in telescoping hood that is keyed so it does not rotate, keeping the engraved markings aligned [1][2]. Construction is anodized aluminum with engraved, paint-filled scales, and the lens is fully rangefinder-coupled through the Leica M bayonet [1][2]. Reviewers note that, like all fast long M lenses, results at f/2 depend heavily on precise rangefinder calibration between lens and body [2].

The lens has been offered in several finishes over its long production run. The standard black anodized version carries order number 11884, with a black-painted version (red footage markings) listed as 11636 and a titanium-finished version as 11632 [1][2]. A chrome/silver version has also been catalogued [1]. Buyers should note that Leica's published specifications have varied slightly over time; the company has quoted weights of roughly 500g, while measured figures for the bare lens are lower [2].

Optical qualities

Rendering The lens is documented as delivering high, even sharpness across the frame at every aperture, with published MTF data among the strongest for any 90mm lens, though on film the practical advantage over Leica's slower 90mm lenses is small [2]. Distortion is described as effectively invisible, and falloff is minor at f/2 and gone by f/2.8 [2].

Bokeh and transitions Background rendering in the central area is regarded as smooth, and the lens can throw distant backgrounds well out of focus, while corner bokeh at f/2 is only fair and out-of-focus foregrounds are less pleasing [2].

Aberrations The apochromatic correction suppresses visible color error, and coma is exceptionally well controlled under normal conditions. One detailed test found that very bright point light sources at f/2 can reveal an unusual high-order coma flare, which clears by about f/4; this is rarely encountered outside extreme cases such as long night exposures of bright lights [2].

History

Development and Launch Leica had produced 90mm rangefinder lenses since the 1930s, and a 90mm f/2 Summicron first appeared in 1958 with a six-element design [2]. A later non-APO, non-aspherical 90mm f/2 was made before this lens [2]. The APO-Summicron-M arrived in 1998 as Leica's premier 90mm, applying apochromatic and aspherical technology to lift wide-open performance above the earlier designs [1][2].

Production Evolution Collector records show production beginning in the late 1990s and continuing across many serial-number batches, with the black anodized 11884 the mainstay and additional silver, black-paint and titanium runs interspersed over the years [1]. Compiled serial-number data documents thousands of examples across these batches from the late 1990s onward [1].

Special editions Beyond the finish variations, the titanium-finished 11632 is the most distinctive factory variant, and a black-paint 11636 with red footage markings was also produced [1][2]. No widely documented military or regional-name factory variants are recorded for this lens.

Collector Notes The standard lens is engraved APO SUMMICRON-M 1:2/90 ASPH and ships with a 55mm front cap, a rear cap and a fitted case [1][2]. Because it is a fast telephoto, buyers should verify focus accuracy against their specific body, as small rangefinder calibration errors are visible at f/2 [2]. The built-in hood, filter thread and engraved scales should be checked for damage, and the finish (black anodized, black paint, silver or titanium) should match the stated order number when assessing value and originality [1][2].

Sources

• [1] Leica Wiki (English). 90mm f/2 ASPH Apo-Summicron-M. https://wiki.l-camera-forum.com/leica-wiki.en/index.php/90mm_f/2_ASPH_Apo-Summicron-M
• [2] Ken Rockwell. LEICA APO-Summicron-M 90mm f/2 ASPH. https://www.kenrockwell.com/leica/90mm-f2-apo-asph.htm