Lens mounts: Canon FD

Pekka Buttler 11/2025

Canon FD mount specifications and identification

Current: 1971–1979
Mount type: Breech lock (locking ring on lens)
Flange focal distance: 42 mm
Film format: 36mm x 24mm (‘Full frame’)
Mount communication: one lever for actuating aperture stop down at time of taking the shot (camera-to-lens); another lever to report aperture selected on lens (lens-to-camera)

Introduction

This article is about the Canon FD mount. The Canon FD mount is the direct successor of the Canon FL mount and the direct predecessor to the Canon new FD (FDn) mount. While there are several similarities between these mounts (and JAPB has previously treated them together), there are also significant differences and mount-specific quirks that merit giving each a separate treatment. Also, these three mounts and their details and significance cannot be adequately discussed in one readable-length article.

Before going further, it is worthwhile to note that the FD-mount is one in a long lineup of Canon interchangeable lens mounts for SLR’s. A short genealogy of the Canon SLR mounts is:

Canon R 1959–1963
Canon FL 1964–1968
(Canon EX 1969–1972)
Canon FD 1971–1979
Canon FDn 1979–1990
Canon AC 1985–1986
Canon EF 1987–2020
Canon EF-S 2003–2020
Canon EF-M 2012–2020
Canon RF 2018–today¹

Back story

The situation leading up to the development and launch of the Canon FD mount was interesting to say the least. SLR cameras had established themselves as the camera technology of choice among both prosumers as well as a majority share of professional photographers. SLRs and their inherent complicatedness did not spook pros or prosumers – these users were not afraid of a learning curve.

The hoi polloi however could not really be bothered to learn how to expose their pictures manually. The idea of having to set both aperture and shutter speed to reflect light conditions for every shot was anathema to these users – most of whom had gotten used to cameras with lighting presets for ‘sunny’, ‘cloudy’ and ‘lightbulb’.

In order for SLR’s to appeal to these masses, nailing exposure had to be automated and it was clear that being able to offer exposure automation – whether shutter priority (user sets shutter speed, camera compensates with aperture) or aperture priority (user sets aperture, camera compensates with shutter speed) – would be able to tap into the considerable market of fundamentally dilettante-esque affluent consumers who wanted to be seen with a serious-looking camera without having to learn the basics of exposure.

In the late 1960s Canon was however ill-suited to take advantage of this market potential. The Company’s premier SLR system – that was well loved by professionals – was using the Canon FL lens mount and that lens mount was unable to facilitate any kind of exposure automation. It did not even support wide-open metering.

On the other hand, and maybe as a stopgap measure, Canon had in 1969 introduced the Canon EX line of cameras and lenses. The Canon EXEE camera was Canon’s first camera to support open aperture metering and moreover it even offered shutter priority auto exposure. However to facilitate tight coordination between lens, aperture, meter and camera the EX system used set lenses (which was less than optimal in its own way).

Hence, as the 1960s became the 70s, it was clear that Canon needed a new lens mount. Preferably one that was future-proof enough for Canon to be able to live with for more than a few years.

The Canon FD system

Against this background it was obvious that the Canon FD mount would implement the requisite interface elements to not only indicate a lens’ maximum aperture, but to also allow the camera to “read” which aperture value the photographer had selected as well as stop down the lens to any value between wide open and stopped all the way down.

While none of the first cameras to be launched for the FD mount yet offered any automatic exposure, it was clear that Canon had already set their sights primarily on shutter priority auto exposure (the photographer sets the shutter speed and the camera’s metering will find the correct aperture for a balanced exposure) and to do this the camera needed to be able to stop down the lens to a specific aperture value.

Most importantly, the actual breech-lock mount of the lens was not changed going from FL to FD. Not only did this mean that FL lenses could be used on FD bodies just as they had been used on FL bodies (using stop-down -metering), this also greatly eased the transition into FD-cameras for photographers who already had an investment into FL-lenses.

1971-1973 Chrome nose lenses

In March 1971 Canon unveiled two new cameras (the F-1 and the FTb), a new lens mount (the Canon FD lens mount) as well as 13 lenses ranging from a 17 mm rectilinear wide-angle to a 300 mm tele lens.

Lens	Design	New design?	Notes
FD17mm f/4	11e/9g	YES	No chrome nose version
FD24mm f/2.8	9e/8g	YES	[data sheet]
FD28mm f/3.5	6e/6g	YES	[data sheet]
FD35mm f/2	9e/8g	YES	[data sheet]
FD35mm f/3.5	6e/6g	NO	[data sheet]
FD50mm f/1.4	7e/6g	NO	[data sheet]
FD50mm f/1.8	6e/4g	NO	[data sheet]
FD55mm f/1.2	7e/5g	NO
FD55mm f/1.2 AL	8e/6g	YES
FD100mm f/2.8	5e/5g	YES	[data sheet]
FD135mm f/2.5	6e/5g	YES	No chrome nose version
FD135mm f/3.5	4e/3g	NO	[data sheet]
FD200mm f/4	6e/5g	YES	No chrome nose version
FD300mm f/5.6	6e/5g	YES	No chrome nose version

An interesting characteristic of these Canon FD lenses introduced in March 1971 was that most of them sported a bayonet attachment for a lens hood² and that that bayonet attachment was chrome-plated to be less likely to be scuffed and marked by the use of lens hoods. These lenses are known as the “Chrome nose” Canon FD lenses.

Chrome nose Canon FD lenses are a bit special, because Canon clearly pulled out all the stops in order to construct some of the most fantastically solid lenses ever. Very typically Canon chrome nose lenses are significantly heavier that the FL lenses they replaced while also being a lot heavier than the (often otherwise identical Canon FD (black nose) lenses that replaced them. Some examples below:

	Canon FL (last version)	Canon FD ‘chrome nose’	Canon FD earliest ‘blacknose’
Canon 28 mm f/3.5	240 g	290 g	250 g
Canon 35 mm f/3.5	270 g	340 g	236 g
Canon 50 mm f/1.4	340 g	370 g	350 g
Canon 135 mm f/3.5	434 g	510 g	465 g

I have no detailed information, but it almost seems as if the Chrome nose lenses used denser metals than any other Canon lenses before or after.

Between March 1971 and February 1973 Canon went on to introduce a tele zoom (the FD100–200/5.6), a fisheye lens (the Fisheye FD 7,5 mm f/5.6) as well as some updated versions of the 50/1.8 and 35/2 designs.

1973–1979 Black nose Canon FD lenses

Starting in February 1973 Canon began overhauling almost its entire lens lineup. While one change was the dropping of the chrome noses for regular black-painted noses, another (marketing-driven) change was to add an acronym denoting the used coating technology to the lens’ name. Hence for instance the Canon FD 50/1.4 (chrome nose) was replaced by the Canon FD 50/1.4 S.S.C. Importantly, the addition (starting in 1973) of advertising the coating technology does not mean that coating technology was added from that day onward, but rather that it became a marketing imperative to highlight the coating.

In this, Canon clearly created a two-tier approach with some lenses being coded as “S.C.” (Spectra coating) or “S.S.C” (Super spectra coating), with the fancier S.S.C coating being denoted in dark red (S.C. was in plain white) with the more pedestrian lenses not being given the Super-treatment.

Finally, as a third change, Canon FD lenses starting to go on a weight-saving diet that would continue all the way to the end of Canon’s manual era.

Lens	1971-1973 version	1973 version	later FD weight (year introduced)
FD17mm f/4	490 g	450 g (S.S.C.)
FD24mm f/2.8	410 g	330 g (S.S.C.)
FD28mm f/3.5	290 g	250 g (S.C.)
FD35mm f/2	420 g	370 g (S.S.C.)	345 g (1976)
FD35mm f/3.5	325 g	295 g (S.C.)	236 g (1977)
FD50mm f/1.4	370 g	350 g (S.S.C.)
FD50mm f/1.8	305 g	255 g (S.C.)	200 g (1976)
FD55mm f/1.2	565 g	565 g (S.S.C.)
FD55mm f/1.2 AL	605 g	575 g (S.S.C.)
FD100mm f/2.8	430 g	360 g (S.S.C)
FD135mm f/2.5	670 g	630 g (S.C.)
FD135mm f/3.5	480 g	465 g (S.C.)	385 g (1976)
FD200mm f/4	725 g	675 g (S.S.C)
FD300mm f/5.6	1155 g	1125 g (S.C.)	685 g (1977)

Late 1970s trends: The proliferation of zooms

The Canon FL lens lineup can be characterised by (among other things) a relative absence of zoom lenses, as only three models were ever produced. In the introduction of the Canon FD mount, the same trend seemed to continue, as among the initial lenses (introduced March 1971) none were zooms, and in the first two years of the mount, Canon introduced just only one zoom lens (the 100-200/5.6)

After the redesigning of the lens lineup in 1973 this increasingly changed as an growing share of the lenses introduced by Canon for the FD mount were zoom lenses until by the time the FD mount was replaced by the new FD mount there were Canon zoom lenses in every category (wide zoom, standard zoom, tele zoom etc.) available.

This trend further coincided with a beginning shift in the perception towards zoom lenses: no longer were zoom lenses uniformly considered to have bad image quality and to be purely for amateurs, instead major camera manufacturers, spearheaded by Canon and some others, started developing zoom lenses which even pro’s could accept to work with.

Adapting Canon FD lenses

If you are in the possession of some nice Canon FD lenses, and want to use them to shoot some film, you have a wide range of opportunities for doing so as the lineup of Canon FD cameras is both wide and many models were manufactured in their millions. Moreover, if you want to you can also use your Canon FD lenses on a Canon FL era body, but you will obviously be limited by that body’s metering abilities. However, due to the short flange focal distance of the Canon FD mount, using Canon FD lenses on any other film camera becomes a rather unpractical (while not entirely impossible) concept.

The issue of the FD mount’s short flange focal distance also is the key impediment should you want to use your Canon FD lenses on any digital SLR. Due to the negative flange focal distance between the Canon FD mount and any of the main dSLR mounts (Canon EF, Minolta A, Nikon F, Pentax K), adapting Canon FD lenses on dSLRs certainly would necessitate an adapter with optics to allow for infinity focusing. Again: Not the optimal solution, but certainly a possibility.

Should your interest be to adapt your Canon FD lens to a mirrorless camera, nothing could be easier as the difference in flange focal distances between the Canon FD mount and any digital mirrorless format is in the double digits. However, due to the design of the Canon FD mount, you will need an adapter that has a control ring that allows you to engage the lens’ aperture stop-down function. Otherwise you’re stuck in using the lens at it’s maximum aperture.

If you’re relatively new to adapting legacy lenses, you might want to have a look at this article on the practicalities of adapting legacy lenses.

The four-ring-problem

But, there is a downside, in that Canon FD lenses are somewhat finicky to use. Due to the way the FD mount (but not Canon FL or Canon FDn mounts) works, adapters always need to have a control ring, that the photographer uses to allow the aperture to reflect those values set on the aperture ring. At a minimum this adds one more ring to the arsenal of rings, that the photographer will need to manipulate.

Moreover, for those who like to be able to use their lenses without their eye leaving the viewfinder, this can lead to confusion – especially on FD lenses, as this results in three rings very close together at the camera-body end of the adapted lens: The aperture close-down ring on the adapter; the breech-lock tightening ring on the lens; the aperture ring; and the focus ring. In the worst-case scenario, the photographer is handling the wrong ring and notices their error only when the lens falls of the adapter.

Footnotes:

1. Technically the Canon RF mount is not an SLR mount because Mirrorless interchangeable lens do not fully qualify as SLR cameras (as there is no mirror), but I’ve added the mount for the sake of anchoring the genealogy in current events. ↩︎
2. The 17/4 was never offered a lens hood by Canon (and hence does not have a ‘chrome nose’, while the 135/2.5; 200/4 and 300/5.6 had integrated, pull-out lens hoods (and hence also do not have a chrome nose). ↩︎