Data sheet: Canon FL 50 mm f/1.4

Pekka Buttler, 07/2024

Specifications

The table below summarizes the lens’ key specifications:

Brand:	Canon	Lens name	FL 50mm 1:1.4
Focal length(s)1	50 mm	Angle-of-view2	46°
Maximum Aperture	f/1.4	In Production	1966–68 (this version) 1965–71 (all variants)
Lens mount	Canon FL	Subfamily (if applicable)	n/a
Length3	45,0 mm	Diameter4	64,1 mm
Filter ring diameter	58 mm	Weight	275 grams
Lens element count	6	Lens group count	5
Aperture blades (S/R/C)5	8 S	Focus throw	150 °
Minimum focusing distance	60 cms	Maximum magnification	1:11,0
Has manual aperture ring	YES	Has Manual focus ring	YES
Aperture mechanism type6	A/M	Aperture click stops	1.4–2–2.8–4–5.6–8–11–16

Further notes:
• The concept of a 50 mm f/1.4 lens – a concept that later became an industry standard – did not exist in Canon’s lens lineup before 1965. Until that point, Canon had preferred a combination of a 58 mm f/1.2 lens and a 50 mm f/1.8 lens.
• There are altogether three distinct variants of the Canon FL 50 mm f/1.4 (See ‘versions’).
• Being a typical representative of the Canon FL lenses of the mid era, this lens has an arrangement (front to back) of an aperture ring, followed by a ring for switching between auto and manual aperture, followed by a focusing ring and the breech-lock tightening ring.
• It sports Canon’s era-typical amber coating.
• The standard lens hood for this lens is the S-60 clamp-on lens hood.

The history of Canon FL lenses

Canon is undoubtedly one of the great names in 35 mm SLR photography. Ever since the 1959 introduction of the Canonflex – Canon’s first interchangeable lens SLR – Canon has constantly focused on being at the forefront of Camera innovation. Often this has necessitated taking stock and redesigning both cameras, lenses and lens mounts. Unlike its archival Nikon, Canon has not tried to integrate all novel features in the same lens mount, but has instead repeatedly launched new, modified mounts to facilitate new features, while still often (but not always) managing to maintain a decent degree of backwards compatibility.

In short (a longer version is here), the development of Canon SLR mounts can be traced as follows:
• 1959–1963: R-mount ⁷. Canon’s first SLR lens mount. Breech lock-type mount with aperture automation (camera is able to stop down lens for taking the shot.
• 1964–1969: FL-mount. Breech-lock type mount, physically similar mount as Canon R-mount, but camera-to-lens communication linkages somewhat different. Cannot communicate selected aperture to body (stop-down-metering only).
• 1970–1978: FD-mount. Breech-lock mount. FD lenses compatible with FL-cameras and vice versa. Manual focus lenses that communicate aperture information to camera, hence opening the door for automatic exposure (both shutter priority and aperture priority possible)
• 1979–1986: new FD-mount (a.k.a. FDn). Bayonet mount, backwards compatible with FL and FD mounts. Otherwise, as FD mount.
• 1987–today: EF-mount. Electronically controlled autofocus lenses that use an internal focusing motor. Compatible with previous mount lenses only using an adapter with optics.

While many see the Canon FL mount lenses as risky oddities compared to the subsequent FD and FDn lenses, Canon’s lineup of FL lenses is not to be frowned at as, in many ways, the FL lenses laid the groundwork for the subsequent success of the FD system. Granted, the coating technology is decidedly dated, and the need for stop-down metering is decidedly a hassle on Canon FD bodies, but especially when adapting lenses on mirrorless cameras, Canon FL lenses offer an interesting value proposition.

Versions

Usually the Canon Camera museum is a trustworthy source of information regarding lens specs’, but in the case of the FL 50 mm f/1.4, the camera museum’s data clearly does not correspond to the samples on hand. This led me down a rabbit hole, and it seems that there’s more to the history of the Canon 50/1.4 than meets the eye.

Based on JAPB’s research in combination with other online sources, it seems Canon used three different optical designs for the FL 50 mm f/1.4. The details of these designs are reiterated below.

Lens / Type	Produced	SN range8	Optical design	aperture type	Weight	More information
FL 50 mm f/1.4 / “Unnamed ring“	1965–1966	???9	6 elements, 4 groups	Dual ring10	unclear11	Seemingly very rare
FL 50 mm f/1.4 / “Auto I“	1966–1968	12151–83191	6 elements, 5 groups	A/M ring, front	275 grams	[this lens]
FL 50 mm f/1.4 / “Auto II”	1968–1971	108129– 275486	7 elements, 6 groups	A/M ring, rear	340 grams	Early samples named “II”12

What is interesting is the progression from a 6/4 through a 6/5 to a 7/6 design. That later design was then repeated in several generations of Canon’s fast fifties.

Adapting

NOTE! Unless noted otherwise, the following applies to all Canon FL lenses:

This lens cannot be used natively on any current SLR or dSLRs. To use it in its native environment, you will need a Canon FL or FD-mount film body.

Thanks to being a fully manual lens (manual aperture, manual focus), the lens can be adapted to all mirrorless cameras using a suitable adapter. However, to be able to stop down the lens, you will need to take one of two routes:

1) Acquire a Canon FD adapter and use its ability to engage the FD/FL lens’ aperture control lever, to make sure that the diaphragm’s opening always reflects the aperture ring’s selection.

2) Acquire a Canon FL adapter (or modify a Canon FD adapter by removing its aperture control lever) and instead set the lens’ aperture mode ring into manual before taking a shot.

Moreover, a large range of special adapters (helicoid adapters, tilt/shift adapters, speed boosters) for using Canon FD (And, hence, Canon FL) lenses on most mirrorless systems are available.

Using Canon FL lenses on dSLRs is a possibility, but is not problem free. Thanks to the relatively short flange focal distance of the Canon FL/FD mount (at 42,0 mm, clearly shorter than that of any full-frame dSLR mount), any adapter will necessitate some optics to achieve infinity focus. Again, a Canon FD adapter should work…

P.S. This lens does not have ‘the bulge’ (see more), which makes adapting it relatively straightforward.

Footnotes

1. Focal length is (unless stated otherwise) given in absolute terms, and not in Full-frame equivalent. For an understanding of whether the lens is wide/tele, see ‘Angle-of-view’. ↩︎
2. Picture angle is given in degrees and concerns the diagonal picture angle. Rule of thumb:
   > 90 ° ==> Ultra-wide-angle
   70–90 ° ==> Wide-angle
   50–70 ° ==> Moderate wide-angle
   40–50 ° ==> ‘Standard’ or ‘normal’ lens
   20–40 ° ==> Short tele lens
   10-20 ° ==> Tele lens
   5-10 ° ==> Long tele lens
   < 5 ° ==> Ultra-tele lens ↩︎
3. Length is given from the mount flange to the front of lens at infinity. ↩︎
4. Diameter excludes protrusions such as rabbit ears or stop-down levers. ↩︎
5. S=straight; R=rounded; C=(almost)circular at all apertures. ↩︎
6. Aperture mechanism types:
   M = Manual
   A = Automatic (manually directed by body)
   P = Preset
   E = Electronic (aperture stopped down through electronic impulse only)
   A/M = Lens supports both A and M and has control to choose between the modes. ↩︎
7. The Canon-R mount should possibly be renamed to (or referred to) as the Canomatic mount to avoid confusion with the modern mirrorless mount that is sometimes also referred to as the Canon R mount. ↩︎
8. Serial number range is based on the study of hundreds of online samples. ↩︎
9. Canon usually did not number production samples below 10000. Hence, whatever the production numbers of the earliest variant, we’re likely only talking about hundreds or a couple of thousands. ↩︎
10. Sources are a bit unclear, but seemingly this first variant of the 50 mm f/1.4 used an aperture ring arrangement very similar to that of the earliest canon FL lenses such as visible on the data sheet of the FL 35 mm f/2.5. This arrangement is characterised by an aperture ring that has a white orientation dot both above and below the (silver) aperture control ring. Of these, the topmost orientation dot indicates the selected aperture and the lower orientation dot (on a ring) is to select the preset aperture. ↩︎
11. One source gives the number of 280 grams. ↩︎
12. Samples in the (roughly) serial number range 108129–152678 are named (on the lens’ name ring) “Canon Lens FL 50mm 1:1.4 II “. Thereafter the II was left out from the lens’ name ring. ↩︎