Can I use Canon FD lenses on a modern Canon EOS DSLR without losing infinity focus?

No — not without an optic-equipped adapter. FD's 42.0 mm flange is 2 mm shorter than EF's 44.0 mm, so a plain mechanical FD-to-EF adapter loses infinity focus (focus stops short of infinity, useful only for close subjects). Adapters with a corrective optical element to restore infinity exist but degrade image quality noticeably. For modern Canon use, mount FD lenses onto an EOS R-series mirrorless body via an FD-to-RF adapter — RF's 20 mm flange leaves comfortable room for a pure mechanical spacer with infinity focus intact.

What's the difference between Canon FD, FL, and R lenses?

Canon R (1959-1964) was Canon's first SLR bayonet, replaced by the simpler Canon FL (1964-1971), then in turn by Canon FD (1971-1992). All three share the same 42.0 mm flange and 48.0 mm throat — the throat dimensions are mechanically compatible — but FD added the open-aperture metering linkage (a tab on the lens that tells the body the maximum aperture) and full-aperture metering that earlier FL lenses lacked. FL lenses physically mount on FD bodies in stopped-down metering mode only; R lenses generally do not because of breech-lock collar differences. None carry electrical contacts.

Is FD glass worth the adapter cost on modern mirrorless?

For the FD L line and the FD 55 mm f/1.2 S.S.C. Aspherical, yes — these are sharper than many vintage primes at the same focal lengths and have distinctive rendering. The FD 85 mm f/1.2 L in particular is widely collected for adapted portrait work. For routine FD primes (FD 50 mm f/1.8, FD 28 mm f/2.8, FD 135 mm f/3.5), modern manual-focus lenses from Voigtländer, Samyang, and 7Artisans deliver better contrast and field flatness at similar prices. Pricing for FD L glass has risen sharply since 2018 as cinematographers discovered the warm, low-microcontrast rendering; budget around $400-1500 for L-series primes second-hand.

Canon · Legacy SLR mount

Canon FD — flange distance, protocol, and adapter compatibility

Canon's manual-focus 35 mm SLR mount, introduced on the F-1 in 1971 and produced through 1992 — Canon's last fully-mechanical bayonet before the all-electronic EF transition in 1987. Two mounting generations share the same lens-to-flange dimensions: the original FD (1971-1979) uses a breech-lock collar (a rotating ring at the lens base, no twisting the lens body itself), and the New FD (1979-1992) switched to a conventional bayonet twist while preserving the same 42.0 mm flange and 48.0 mm throat. Pure mechanical: aperture-priority and shutter-priority both communicate via mechanical linkages, no electrical contacts in any iteration. The FD L line — FD 50 mm f/1.4 S.S.C., FD 85 mm f/1.2 L, FD 135 mm f/2 L, FD 200 mm f/1.8 L, FD 300 mm f/4 L — and the legendary FD 55 mm f/1.2 S.S.C. Aspherical remain the most sought-after FD glass for mirrorless adaptation. The 42 mm flange is shorter than EF / Nikon F / Pentax K / Minolta SR, so FD-to-EF / FD-to-Nikon-F (without a corrective optic) cannot reach infinity — FD glass is mirrorless-only territory in practice.

Mount specifications

Flange focal distance: 42 mm
Throat diameter: 48 mm
Electronic protocol: Mechanical only (no electronic coupling)
Supported formats: full-frame, APS-C
Manufacturer: Canon
Introduced: 1971 (discontinued)
Status: Discontinued

Canon FD on the flange-distance axis

Canon FD sits at 42 mm — highlighted in orange below. The flange-distance gap between the mirrorless and SLR clusters is the room a mechanical adapter occupies; that gap is why almost every SLR lens adapts onto every mirrorless body, and why the reverse is mechanically impossible.

Flange focal distance (mm)SLR / DSLRMirrorlessRangefinderMedium-format mirrorlessCinemaLegacy SLR

Adapting Canon FD lenses onto other bodies

You own Canon FD glass and want to mount it on a body with a different lens mount. Rows are sorted by feasibility.

Body mount	Result	Adapter examples	Caveats
Body mount Canon RF flange 20 mm	Mechanical MFno ISAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon FD lens and Canon RF body.
Body mount Canon EF-M flange 18 mm	Mechanical MFno ISAp. ring1.5× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon FD lens and Canon EF-M body.
Body mount Nikon Z flange 16 mm	Mechanical MFno ISAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon FD lens and Nikon Z body.
Body mount Sony E (incl. FE) flange 18 mm	Mechanical MFno ISAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon FD lens and Sony E (incl. FE) body.
Body mount Fujifilm X flange 17.7 mm	Mechanical MFno ISAp. ring1.5× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon FD lens and Fujifilm X body.
Body mount Fujifilm GFX (G-mount) flange 26.7 mm	Mechanical MFno ISAp. ringvignettes	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon FD lens and Fujifilm GFX (G-mount) body.
Body mount Micro Four Thirds flange 19.25 mm	Mechanical MFno ISAp. ring2× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon FD lens and Micro Four Thirds body.
Body mount L-Mount flange 20 mm	Mechanical MFno ISAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon FD lens and L-Mount body.
Body mount Leica M flange 27.8 mm	Mechanical MFno ISAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon FD lens and Leica M body.
Body mount Canon RF (cine) flange 20 mm	Mechanical MFno ISAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon FD lens and Canon RF (cine) body.
Body mount C-mount flange 17.526 mm	Mechanical MFno ISAp. ring2.7× crop	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon FD lens and C-mount body.
Body mount Canon EF flange 44 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only -2.0 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Canon FD lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a Canon EF (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.
Body mount Canon EF-S flange 44 mm	Speed booster MFIS lens-onlyAp. wheel1.5× crop	Speed Booster / focal-reducer family	Flange clearance is only -2.0 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Canon FD lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a Canon EF-S (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.
Body mount Nikon F flange 46.5 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only -4.5 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Canon FD lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a Nikon F (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.
Body mount Sony A / Minolta A flange 44.5 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only -2.5 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Canon FD lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a Sony A / Minolta A (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.
Body mount M42 (Pentax / Praktica screw mount) flange 45.46 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only -3.5 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Canon FD lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a M42 (Pentax / Praktica screw mount) (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.
Body mount Pentax K flange 45.46 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only -3.5 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Canon FD lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a Pentax K (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.
Body mount PL (Positive Lock) flange 52 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only -10.0 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Canon FD lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a PL (Positive Lock) (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.
Body mount Canon EF (cine) flange 44 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only -2.0 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Canon FD lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a Canon EF (cine) (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.
Body mount Exakta flange 44.7 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only -2.7 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Canon FD lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a Exakta (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.
Body mount Praktica B flange 44.4 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only -2.4 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Canon FD lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a Praktica B (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.
Body mount Konica AR flange 40.5 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only 1.5 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Canon FD lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a Konica AR (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.
Body mount Minolta SR / MC / MD flange 43.5 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only -1.5 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Canon FD lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a Minolta SR / MC / MD (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.
Body mount Olympus OM flange 46 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only -4.0 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Canon FD lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a Olympus OM (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.
Body mount Contax/Yashica (C/Y) flange 45.5 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only -3.5 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.	Speed Booster equivalence calculator Plug in any Canon FD lens and pick the focal-reducer family. The calc returns the effective focal length and aperture on a Contax/Yashica (C/Y) (APS-C), plus the full-frame equivalent angle of view after the body's crop stacks on top. Lens focal length (mm)Max aperture (f/N)Focal-reducer family Effective focal length 35.5 mm 50.0 mm × 0.71 on the reducer. Effective aperture f/1.28 0.99 stops brighter than f/1.80. Full-frame equiv. angle of view 53.3 mm 35.5 mm × 1.5× (APS-C sensor crop). A focal reducer concentrates the lens's image circle, so both focal length and f-number scale by the same ratio (stops gained = `−2 · log₂(ratio)`). The body's crop factor still applies on top — the full-frame-equivalent angle-of-view multiplier is ratio × body crop. Calculator is informational; verify against the adapter vendor's per-lens compatibility chart before purchase.

Adapting other lenses onto a Canon FD body

You own a Canon FD body and want to mount glass from other systems. Mirrorless-lens-onto-DSLR-body combinations are omitted (rear element collides with the mirror box).

Lens mount	Result	Adapter examples	Caveats
Lens mount Canon EF flange 44 mm	Mechanical MFIS lens-onlyAp. wheel	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon EF lens and Canon FD body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
Lens mount Canon EF-S flange 44 mm	Mechanical MFIS lens-onlyAp. wheelvignettes	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon EF-S lens and Canon FD body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
Lens mount Nikon F flange 46.5 mm	Mechanical MFIS lens-onlyAp. wheel	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Nikon F lens and Canon FD body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
Lens mount Sony A / Minolta A flange 44.5 mm	Mechanical MFIS lens-onlyAp. wheel	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Sony A / Minolta A lens and Canon FD body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
Lens mount M42 (Pentax / Praktica screw mount) flange 45.46 mm	Mechanical MFno ISAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between M42 (Pentax / Praktica screw mount) lens and Canon FD body.
Lens mount Pentax K flange 45.46 mm	Mechanical MFIS lens-onlyAp. wheel	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Pentax K lens and Canon FD body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
Lens mount PL (Positive Lock) flange 52 mm	Mechanical MFno ISAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between PL (Positive Lock) lens and Canon FD body.
Lens mount Canon EF (cine) flange 44 mm	Mechanical MFIS lens-onlyAp. wheel	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Canon EF (cine) lens and Canon FD body. Lens has no aperture ring; choose an adapter with a built-in aperture-control wheel.
Lens mount Exakta flange 44.7 mm	Mechanical MFno ISAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Exakta lens and Canon FD body.
Lens mount T-mount (T2) flange 55 mm	Mechanical MFno ISAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between T-mount (T2) lens and Canon FD body.
Lens mount Praktica B flange 44.4 mm	Mechanical MFno ISAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Praktica B lens and Canon FD body.
Lens mount Olympus OM flange 46 mm	Mechanical MFno ISAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Olympus OM lens and Canon FD body.
Lens mount Contax/Yashica (C/Y) flange 45.5 mm	Mechanical MFno ISAp. ring	generic mechanical adapter ring (multiple vendors)	Mechanical adapter only — no electronic communication between Contax/Yashica (C/Y) lens and Canon FD body.
Lens mount Konica AR flange 40.5 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only -1.5 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.
Lens mount Minolta SR / MC / MD flange 43.5 mm	Speed booster MFIS lens-onlyAp. wheel	Speed Booster / focal-reducer family	Flange clearance is only 1.5 mm — a plain mechanical adapter cannot reach infinity focus; a focal reducer (Speed Booster) with optical glass is required. Speed Boosters typically widen the effective focal length (~0.71×) and add ~1 stop of light, which can be desirable on crop bodies.

Adapter SKU teardown

Curated adapter SKUs that involve the Canon FD mount on either side, with the operational specifics — body-side electronic contact count, firmware-update path, weather sealing, and whether optical glass is in the path.

Fotodiox FD-RF
released 2019
Canon FD lens → Canon RF body
- no firmware updates
- not weather sealed
- no glass — pass-through
- Canon FD / FL breech-lock and New FD (FDn) bayonet lenses onto Canon RF bodies. Mechanical-only — Canon abandoned FD in 1987 and never made a first-party FD→RF adapter, so a third-party ring (Fotodiox / Urth / K&F) is the only path. No AF, no electronics.
- Built-in aperture actuator: FD lenses sit wide open off-camera, so the adapter holds the stop-down lever and the lens's own aperture ring then controls the diaphragm. The 42 mm FD flange clears RF's 20 mm by 22 mm — glassless, infinity preserved.
Fotodiox FD-NEX
released 2011
Canon FD lens → Sony E (incl. FE) body
- no firmware updates
- not weather sealed
- no glass — pass-through
- Canon FD / FL and New FD lenses onto Sony E. Mechanical ring with a built-in aperture actuator that holds the FD stop-down lever so the lens's aperture ring works. No AF, no electronics.
- The 42 mm FD flange clears Sony E's 18 mm by 24 mm — glassless, infinity preserved. Compact FD primes (50/1.4 SSC, 28/2.8) suit small α bodies; the cult FD 55 mm f/1.2 SSC Aspherical and 85 mm f/1.2 L are the headline adapts.

References

Common questions

Can I use Canon FD lenses on a modern Canon EOS DSLR without losing infinity focus?: No — not without an optic-equipped adapter. FD's 42.0 mm flange is 2 mm shorter than EF's 44.0 mm, so a plain mechanical FD-to-EF adapter loses infinity focus (focus stops short of infinity, useful only for close subjects). Adapters with a corrective optical element to restore infinity exist but degrade image quality noticeably. For modern Canon use, mount FD lenses onto an EOS R-series mirrorless body via an FD-to-RF adapter — RF's 20 mm flange leaves comfortable room for a pure mechanical spacer with infinity focus intact.
What's the difference between Canon FD, FL, and R lenses?: Canon R (1959-1964) was Canon's first SLR bayonet, replaced by the simpler Canon FL (1964-1971), then in turn by Canon FD (1971-1992). All three share the same 42.0 mm flange and 48.0 mm throat — the throat dimensions are mechanically compatible — but FD added the open-aperture metering linkage (a tab on the lens that tells the body the maximum aperture) and full-aperture metering that earlier FL lenses lacked. FL lenses physically mount on FD bodies in stopped-down metering mode only; R lenses generally do not because of breech-lock collar differences. None carry electrical contacts.
Is FD glass worth the adapter cost on modern mirrorless?: For the FD L line and the FD 55 mm f/1.2 S.S.C. Aspherical, yes — these are sharper than many vintage primes at the same focal lengths and have distinctive rendering. The FD 85 mm f/1.2 L in particular is widely collected for adapted portrait work. For routine FD primes (FD 50 mm f/1.8, FD 28 mm f/2.8, FD 135 mm f/3.5), modern manual-focus lenses from Voigtländer, Samyang, and 7Artisans deliver better contrast and field flatness at similar prices. Pricing for FD L glass has risen sharply since 2018 as cinematographers discovered the warm, low-microcontrast rendering; budget around $400-1500 for L-series primes second-hand.