Leica Summicron-M 35mm f/2 ASPH. I

Leica Summicron-M 35mm f/2 ASPH. I

The 35mm Summicron line reaches back to the 1950s, but the aspherical version introduced in the mid-1990s marked a clean break from the double-Gauss formulas that defined every earlier model. Using computer-aided design and an element with aspherical surfaces, Leica reworked the optic into a more complex seven-element, five-group layout that traded a little of the older lenses' tiny size for markedly higher correction, especially at full aperture [1][2]. Many collectors and reviewers treat this lens as the fifth version of the 35 Summicron, usually referring to it simply as the "ASPH," and it is widely regarded as the lens that epitomizes the modern Leica M wide-angle: compact, high-performing, and an obvious match for the 35mm frame lines on most M bodies.

Build and handling follow Leica's house style closely. The black version uses an anodized aluminium outer barrel while the chrome version is made from brass and is heavier but more hardwearing, with the rear mount made of chromed brass. The lens is small for its specification but feels dense in the hand because of its all-metal construction and large glass elements, and its convex rear element pushes the weight distribution back toward the mount, so it balances well once fitted. Focusing uses a comfortable tab with a smooth, fairly long throw, and the finely ribbed aperture ring clicks in full and half stops. As an M-bayonet lens it is rangefinder-coupled, and on the M system it covers the 35mm frame lines naturally. Reviewers note it is small enough that it does not intrude noticeably into the viewfinder, an advantage often cited when choosing it over the larger 35mm Summilux[3]. The lens accepts 39mm filters and ships with a well-regarded hood; a rectangular plastic hood with a matching cap was supplied with earlier examples, with a more traditional vented metal hood also available.

This first aspherical Summicron has gone through running changes during its long production. Later examples carry Leica's 6-bit coding on the bayonet for automatic lens identification on digital M bodies, while earlier ones do not. The lens has been offered in black aluminium and chromed brass, along with a number of special finishes such as black paint, titanium and black chrome, and all versions are made in Germany. A revised model usually called the ASPH II keeps the same optical design but adds aperture blades, swaps in a metal hood with a cut-out to reduce viewfinder blockage, and makes minor cosmetic changes; one source dates that update to 2016. The black and chrome variants of the original ASPH carry separate Leica order numbers, and buyers should match the finish to the correct catalogue number when verifying a copy.

Optical qualities

Rendering The lens is generally described as having a modern, transparent signature that depicts subjects faithfully without adding strong character of its own, prioritizing accuracy and balance over an obviously stylized look.

Sharpness Resolution and contrast are reported as excellent even wide open at f/2, with high definition across most of the frame and only a subtle mid-field dip attributed to traces of astigmatism; performance is essentially optimal by f/4 across the field. Other reviewers simply note that the lens is very sharp once stopped down.

Contrast and color Color is described as highly saturated yet natural, with good separation between similar tones, while global and mid-level contrast is high enough that it can occasionally look a little harsh in strong light, particularly in black and white.

Bokeh and transitions For a mid-speed 35mm lens the out-of-focus rendering is considered better than most peers, with reasonably soft blur-disc edges and few double lines, though some texture remains in defocused areas given the focal length and aperture.

Flare resistance, distortion and vignetting Flare is well controlled, with only occasional ghosting under oblique, high-intensity light; distortion amounts to a very subtle pincushion at the frame edges, and vignetting is close to two stops wide open, easing to about a stop by f/4.

Aberrations Color fringing and coma are reported as well controlled, with a slight focus shift and minor field curvature visible only under close scrutiny; the eight-bladed diaphragm produces eight-point sunstars when stopped down.

Digital use On digital M bodies the lens performs well, with 6-bit coding simplifying correction; on adapted mirrorless cameras such as the Sony A7 series, ray-angle issues can reduce off-center contrast at wider apertures, improving substantially when stopped down.

History

Development and Launch The aspherical Summicron 35 replaced a long series of double-Gauss designs and entered production in the mid-1990s, with the new optical layout made practical by computer-aided design and more advanced manufacturing. It positioned Leica's mid-speed 35mm offering as a high-correction modern lens sitting below the faster 35mm Summilux in the lineup while remaining substantially more compact.

Production Evolution During its run the lens gained 6-bit coding on the bayonet for digital identification, and Leica later released a revised ASPH II using the same optical design but with additional aperture blades, a metal hood, and minor cosmetic changes, an update one source places in 2016.

Special editions Beyond the standard black aluminium and chrome brass finishes, the lens has appeared in special finishes including black paint, titanium and black chrome.

Collector Notes Buyers should confirm whether a given example has 6-bit coding, since this affects automatic correction on digital bodies, and should match the finish to the correct catalogue number. Note that the original ASPH and the later ASPH II are easily confused; the blade count and hood type are useful identifiers, and the two share the same optical formula. One reviewer observes that this version focuses a few centimetres closer than its marked 0.7m minimum, which can cause slight front focus if you rack the ring fully against the stop while relying on the rangefinder. As a long-lived Leica lens it holds value well on the used market but, like any M lens, benefits from a service check before purchase.