Leica Summilux-M 21mm f/1.4 ASPH.

Leica Summilux-M 21mm f/1.4 ASPH.

When it appeared, the Summilux-M 21mm f/1.4 ASPH. stood out as the fastest wide-angle lens ever offered for the Leica M system, pairing an ultra-wide angle of view with an f/1.4 maximum aperture that almost no other rangefinder lens of this focal length had matched [1][2]. The order number 11647 identifies the standard black anodized production lens, which Leica has kept in the catalogue since 2008. For collectors and photographers, its appeal rests on this unusual combination of speed and coverage in a relatively compact M-mount body, along with the rendering character that comes from a fast aspherical wide-angle design.

Optically the lens uses ten elements in eight groups, with a floating element that maintains image quality across the focusing range down to its 0.7 m close limit[3]. Leica describes the design as strongly correcting vignetting and distortion, and the floating group is intended to hold quality at close distances. The aperture runs from f/1.4 to f/16 and is set manually with click stops including half values, and the diaphragm uses eleven blades. The barrel is built from anodized aluminium and optical glass, focuses by hand, and couples to the rangefinder; rather than a conventional threaded front filter, it accepts Series VIII filters mounted within its dedicated rectangular hood. The lens carries a six-bit code (101111) so digital M bodies can recognise it, even though it is read optically rather than being a routine user setting.

There are no widely documented optical variants of this lens; it has been produced as a single black anodized version under model number 11647 throughout its run, with the engraving SUMMILUX-M 1:1.4/21 ASPH. Listed weight is about 580 g and the barrel measures roughly 66 mm long and about 70 mm in diameter, extending further with the hood fitted. Because the front filter system is the in-hood Series VIII type rather than a screw-in thread, buyers should treat the correct hood (Leica part 12461) and the matching external finder as part of a complete outfit.

Optical qualities

Rendering This lens is generally described as favouring character over clinical uniformity. Reviewers note a soft glow wide open at f/1.4 that gradually gives way to higher sharpness as the lens is stopped down, with strong central sharpness reached around the middle apertures while corners retain some of the softer look [4].

Sharpness At f/1.4 the centre shows a soft, glowing quality rather than crisp detail; sharpness builds as the aperture closes, with notable improvement by roughly f/2.4, though the extreme corners remain comparatively soft even stopped down.

Contrast and color Color rendering is reported as pleasing and reasonably accurate across most apertures, with the wide-open glow lending images a softer, dreamier look when shooting near maximum aperture.

Bokeh and transitions Out-of-focus highlights take on a variety of shapes rather than uniformly round discs, a trait reviewers attribute partly to residual aberration; the result is described as distinctive and varied rather than perfectly smooth.

Flare resistance Flare behaviour is varied and easy to provoke, especially with the hood removed, producing effects ranging from soft streaks to ghosting and arc-shaped patterns depending on light angle.

Distortion and vignetting Leica states the design strongly suppresses vignetting and distortion, and reviewers describe barrel distortion as very difficult to detect in normal use.

Aberrations Some residual aberration remains; in demanding subjects such as point light sources it can prevent perfectly circular rendering, which also contributes to the lens's varied bokeh shapes.

History

Development and Launch The Summilux-M 21mm f/1.4 ASPH. was introduced in 2008 as the fastest wide-angle lens in the M lineup, extending the Summilux name to an ultra-wide focal length. It was positioned as a high-end, specialist optic for photographers wanting both very wide coverage and an exceptionally large aperture on the M system.

Production Evolution The lens has remained in production as a single black anodized configuration under order number 11647, without widely documented optical or finish revisions. Collector serial-number records place early examples from around 2008 onward, with substantial numbers assigned in the following years.

Special editions No major factory special editions or alternative finishes of this lens are widely documented; it is generally encountered only in its standard black anodized form.

Collector Notes Because the filter system is the in-hood Series VIII type rather than a screw-in front thread, buyers should confirm that the correct rectangular hood (part 12461), front cap, and an appropriate external bright-line finder (such as 12024 or 12025) are present, since these accessories are integral to using the lens and costly to replace. Confirm that the six-bit coding and engraving (SUMMILUX-M 1:1.4/21 ASPH.) match a genuine 11647 example, and check the front element and floating-group barrel for haze, fungus, or impact damage as with any large, complex wide-angle.