The Canon 85mm f/1.5 I is a fast Gauss-type LTM portrait lens of 1952, prized by Leica screw-mount collectors for its chrome build and rare optics.</parameter> <parameter name="long_description">## Canon 85mm f/1.5 I Among the fastest medium telephotos offered for Leica thread-mount cameras in the early 1950s, the Canon 85mm f/1.5 I was Canon's attempt to push the short-telephoto rangefinder lens to a wider aperture than most competitors of its day. Marketed in June 1952 under the Serenar name, it used a seven-element, four-group Gauss-type design and was developed from the earlier Serenar 85mm f/1.9 I of 1951, gaining a roughly one-stop wider maximum aperture in the process [1]. The same lens was sold both as a Serenar and later under the Canon brand name, reflecting the company's transition away from the Serenar label during the 1950s. The lens is a relatively heavy, chrome-finished optic built around a brass barrel, which accounts for its substantial weight in this first version. It carries a high blade count diaphragm for a smooth, near-circular aperture, focuses to one meter, and accepts screw-in filters on its front thread. As an early Canon screw-mount telephoto it mounts on Leica thread-mount (LTM/M39) bodies and the contemporary Canon rangefinders, and like most lenses of this type it relies on the camera body's rangefinder for focusing rather than on any electronic coupling. According to Canon's own records, the first version was subsequently improved into the Serenar 85mm f/1.5 II, which substituted a lighter aluminum-alloy barrel to reduce weight while retaining the same basic optical concept. The chrome first version is the heavier of the two and is the one most associated with the original Serenar branding. Collectors should be aware that 85mm f/1.5 lenses in the Canon line appear under both Serenar and Canon markings, and finish and engraving details are the main way to distinguish early from later barrels. --- ## Optical qualities **Rendering** Documented information on this specific lens is limited, so claims about its rendering should be treated cautiously. As a fast Gauss-type design from the early 1950s it would be expected to show the wide-open character typical of large-aperture lenses of its era, with best sharpness and contrast reached on stopping down. Its 20-blade diaphragm produces a nearly round aperture opening, which favors smooth out-of-focus highlights when the lens is closed down slightly. Beyond these design-based observations, there is little consistently sourced reviewer consensus on its rendering, and specific performance figures are not well documented. --- ## History **Development and Launch** Canon introduced the Serenar 85mm f/1.5 I in June 1952 as a large-aperture middle telephoto for its rangefinder system. It was based on the Serenar 85mm f/1.9 I of 1951 and represented a faster development of that earlier portrait-length lens, retaining a Gauss-type layout of seven elements in four groups. **Production Evolution** Canon records indicate the design was carried forward into the Serenar 85mm f/1.5 II, which replaced the original barrel with a lighter aluminum-alloy construction; the lens was also offered under the Canon brand name as the company phased out the Serenar designation. **Special editions** No major factory special editions, military variants, or unusual finishes of the 85mm f/1.5 I are widely documented; the principal distinction within the family is between the chrome first version and the lighter aluminum-barrel second version. **Collector Notes** This is a relatively uncommon early Canon fast telephoto, and auction and dealer records place values that rise sharply with condition, with clean examples commanding a considerable premium over average ones [2]. Buyers should confirm whether a given lens is the chrome first version or the later aluminum-barrel II, check the front element and internal glass for the haze and coating degradation common to early-1950s lenses, and verify that the diaphragm operates smoothly given the high blade count. Because the design was sold under both Serenar and Canon markings, name engraving alone does not always indicate version, so barrel material and finish should be checked as well. --- ## Sources * [1] Canon Camera Museum. *Serenar 85mm f/1.5 I*. https://global.canon/en/c-museum/product/s23.html * [2] CollectiBlend. *Canon 85mm (8.5cm) f1.5 Serenar (SM, chrome) price guide*. https://collectiblend.com/Lenses/Canon/85mm-f1.5-Serenar-(SM,-chrome).html

Canon 85mm f/1.5 I

LTM mount