Data sheet: Canon FDn 35-70 mm f/4

Pekka Buttler, 12/2023

Specifications

The table below summarises the lens’ key specifications (measurements based on pictured sample):

Brand:	Canon	Lens name	FD 35-70mm 1:4
Focal length(s) 1	35-70 mm	Angle-of-view 2	18°
Maximum Aperture	f/4	In Production	1979–1983
Lens mount	Canon FD	Subfamily (if applicable)	FDn (“New FD”)
Length 3	86,7 mm	Diameter 4	63,0 mm
Filter ring diameter	52 mm	Weight	306 grams
Lens element count	8	Lens group count	8
Aperture blades (S/R/C) 5	6 S	Focus throw	180 °
Minimum focusing distance	≈0,5 m	Maximum magnification	1:6,7
Has manual aperture ring	YES	Has Manual focus ring	YES
Aperture mechanism type	Automatic	Aperture click stops 6	4•5.6•8•11•16•22

Further notes:
• This was Canon’s first kit zoom for the new FD system, and it was introduced in 1979 together with the other almost 30 modernised lenses that made up the beginning of the new FD (FDn) system.
• The Canon FDn 35–70mm f/4 is a very compact consumer-grade zoom lens, that features a constant maximum aperture, a lens construction that does not change size during zooming or focusing. The filter ring however rotates during focusing.
• The focus ring doubles as a rudimentary lens hood, meaning that the filter threads are (at many focal lengths) recessed quite deeply within the filter ring/lens hood. This makes using a polarising filter quite problematic, and also makes it a bit tricky to use a lens cap (a lens cap with an internal pinching arrangement is a must)
• This lens was replaced in Canon’s lineup in 1983 by the Canon FDn 35-70mm f/3.5-4.5
• While I have not taken one of these lenses apart, I do suspect that the materials quality of the lens is ‘consumer grade’, because all the samples (3 and counting) that I have come across show signs of mechanical wear (especially an uneven zoom ring)

History of Canon FD 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 arch-rival 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.

The era of the Canon FD mount can be characterised by a gradual shift towards the ever-increasing use of plastics and lighter materials (see some more in the JAPB article on the Canon FL, FD and FDn mounts). In the chronology of this gradual shift:
• ‘Chrome nose’ FD lenses (1971–1973) are solid metal (often brass) and glass.
• Black nose FD lenses (1973–1979) are also metal and glass, but especially later, Mk II and III variants have shifted to using less metals and lighter metals.
• FDn lenses (1979–1987) typically make extensive use of plastics.

Another noteworthy point is related to the S.C. and S.S.C. acronyms found on some FD lens’ name rings: S.C. stands for “spectra coating”, while S.S.C. stands for “super spectra coating”. Both are proprietary marketing names for Canon’s optical coating technology. In theory S.S.C. is always a superior form of coating, but that does not mean that one should always try to get an S.S.C. lens, because:
• S.C. and S.S.C. are first and foremost marketing terms, that were not used on early Canon FD lenses, nor on most FDn lenses. Hence, a FDn lens is certain to have at least the level of coating of its direct (FD) predecessor, even though the S.S.(C.) marking is missing from the lens.
• Coating technology developed a lot during the 70s and 80s. A late S.C. coating is liable to be better optimised than an early S.S.C. coating.
• While FDn versions no longer sported the S.C. or S.S.C monikers, their coatings are always at least as good as that of their direct predecessor in the Canon FD line.

Related versions

This is Canon’s first stab at making a consumer-grade 35–70 mm standard zoom (Since the 1973 Canon FD 35-70mm f/2.8–3.5 S.S.C, Canon has also produced pro-level standard lenses).

The entire lineup of Canon consumer-grade standard zooms in the 35–70 focal length range are (data based on Canon Camera museum):
• FDn 35–70mm f/4 (1979–1983), 8 elements in 8 groups, 315 grams [this lens]
• FDn 35-70mm f/3.5–4.5 (1983–?), 9 elements in 8 groups, 200 grams
• EF 35–70mm f/3.5–4.5 (1987–?), 9 elements in 8 groups, 245 grams

In the late 80s the 35-70mm recipe fell out of favour. Instead the next decades saw the introduction of 28–70 mm standard zooms as well as 35-80 mm standard zooms, that quickly merged into first 28-80 mm and later 28-90 mm standard zooms.

Adapting

This lens cannot be used natively on any current SLR or dSLRs. To use it in its native environment, you will need a Canon FD or FL-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, for the adapter to allow the lens to stop down, you will need an adapter that can be set to engage the FD lens’ aperture control lever.

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

Using Canon FD lenses on dSLRs is a possibility, but is not problem free. Thanks to the relatively short flange focal distance of the Canon 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.

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. Numbers equal aperture values on aperture ring; • intermediate click; – no intermediate click. ↩︎
7. The Canon-R mount should possibly be renamed to (or referred to) as the Canonflex mount to avoid confusion with the modern mirrorless mount that is sometimes also referred to as the Canon R mount. ↩︎