OVERVIEW

The Canon 100mm F2 Serenar was introduced in 1959 and produced for around ten years. Perhaps unknown to some, Canon produced rangefinders before making SLRs. The Canon S-Mount is a Leica M39 screw mount and is focus coupled - meaning the lenses will work on a Leica M rangefinder via a standard M39 to Leica M adapter. Canon continued to evolve the 100mm Serenar’s optical design and it continued in several of Canon’s early SLR lenses in the 60‘s and early 70‘s. In 1959 the 100mm F2 Serenar’s MSRP price was 33,000 Yen, or ~$91 in US dollars at the fixed exchange rate. In today’s dollars the price would be $750-$1250 depending on how one adjusts for inflation and purchasing power.

BUILD QUALITY

As one would expect from a 1960’s vintage lens, the lens is metal, with more metal and some added metal for extra measure. Add a black lacquer piano finish with some matte finish silver bits, and it is classy looking as lenses go. The 100mm Serenar’s build quality is wonderful. The lens is solid with no wobble or play, manual focus is smooth (though slightly heavy) and the aperture ring click decisively from stop-to-stop in whole stop increments. Being a screw mount lens, a M39 to Leica M-mount adapter is needed; I opted for a Voigtlander 28/90.

The front lens cap is the press-on type. My first Canon 100mm Serenar had a black plastic front cap with a metal dome insert with the Canon logo in silver. My current one has a silver colored aluminum cap. A separate lens hood slips over the lens barrel and a small thumb screw holds the lens hood in place, pressing a ring against the lens barrel. Lenses with a red “EP” in a red diamond marking on the front retaining ring indicate that the lens was sold at a military exchange post, supposedly this makes the lens more collectible. There is some debate as to what the “EP actually standards for, perhaps “Exchange Post” or “Exchange Program”. There is no doubt that the lenses were sold at US military PX/BX stores.

OPTICAL DESIGN

Jiro Mukai is credited for the 100mm F2 Serenar’s design (along with several other Canon lenses). His work was based in part on earlier designs (and patents) from Hiroshi Ito, who refined Canon’s gaussian optical design for use with faster apertures (reducing aberrations). The lens diagram is from a patent for a 6 lens, 4 group optical design is similar to the 100mm F2 Serenar:

Diagram from Canon’s U.S. Patent 2681594, Issued June 1954

It is unknown (at least to me) if the above graphic is for the Canon 100mm F2 Serenar or one of the other 85mm Serenars. The 85mm F1.9 came first, then the 85mm F2 and 100mm F2 and then 85mm F1.8 was the last one.