Using vintage manual lenses on a mirrorless camera
M42, Canon FD, Nikon F, Pentax K and Leica M lenses adapt easily to mirrorless. How to focus them, set the aperture, and avoid adapters that miss infinity.
Almost any manual-focus lens from the film era can be used on a modern mirrorless camera with a simple, glass-free adapter ring. M42, Canon FD, Nikon F, Pentax K and Leica M lenses all adapt to Sony E, Nikon Z, Fujifilm X, Canon RF, L-Mount and Micro Four Thirds. You focus by hand using focus peaking or magnified live view, set the aperture on the lens, and let the camera meter in aperture priority. The two things that go wrong are lenses whose aperture is controlled by the camera, and cheap adapters that are machined to the wrong thickness.
Why mirrorless brought old lenses back
Every lens is designed to sit a fixed distance from the film or sensor: its flange focal distance. SLR lenses were designed around a mirror box, so their flange distances are long. Mirrorless bodies have no mirror and very short flange distances. That leaves a gap which a plain tube can fill, putting the old lens exactly where it expects to be. The principle is covered in flange focal distance explained.
The second reason is the viewfinder. A mirrorless camera shows the image straight from the sensor, so it can highlight in-focus edges and magnify part of the frame. That makes accurate manual focus far easier than judging sharpness by eye on an optical focusing screen.
Which old mounts adapt easily
| Lens mount | Flange distance | Aperture control | Notes |
|---|---|---|---|
| M42 screw | 45.46 mm | Ring on the lens | Cheapest entry point; dozens of makers |
| Canon FD | 42.0 mm | Ring, but see the lever below | Orphaned by Canon, so cheap |
| Nikon F | 46.5 mm | Ring on older lenses; none on G and E types | Longest flange of the group |
| Pentax K | 45.46 mm | Ring on older lenses; none on DA types | Unbroken since 1975 |
| Leica M | 27.8 mm | Ring on the lens | Rangefinder, so a much shorter flange |
Every current mirrorless mount has a shorter flange distance than all of these: 16.0 mm for Nikon Z, 17.7 mm for Fujifilm X, 18.0 mm for Sony E, 19.25 mm for Micro Four Thirds, and 20.0 mm for Canon RF and L-Mount. So each combination has room for an adapter. Adapter pages with the exact margins include M42 on Sony E, Canon FD on Sony E and Leica M on Nikon Z.
Focusing: peaking and magnification
Two camera features do the work.
Focus peaking outlines the sharpest edges in a colour of your choice. It is quick and good for stopped-down work, but it is not precise at wide apertures, where the zone of sharpness is thin and peaking can light up slightly in front of or behind the true focus.
Magnified view enlarges part of the frame in the viewfinder. It is slower but exact, and it is the one to use for a portrait at f/1.4.
With a plain adapter the camera cannot tell when you turn the focus ring, so any setting that magnifies automatically on focus-ring movement will not trigger. Assign magnification to a button instead. Sony and Canon mirrorless bodies also have a menu setting (“Release w/o Lens” on Sony, “Release shutter w/o lens” on Canon) that must be enabled before the camera will fire with an adapter that has no contacts.
Aperture rings, and the lenses without them
A plain adapter has no electronics, so the camera cannot close the aperture. The lens needs its own aperture ring, and the camera meters through the stopped-down lens. Aperture priority works normally; the camera simply records no aperture value in the EXIF.
M42 and Leica M lenses have aperture rings throughout. Three cases need care.
Canon FD: the aperture lever
FD lenses were designed to stay wide open until the moment of exposure, when a lever in the camera stopped them down. On an adapter nothing moves that lever, so the aperture ring appears to do nothing. FD adapters solve this with a ring or switch, usually marked lock and open, or A and M, that holds the lever in the stopped-down position. Set it once and the aperture ring works normally. If an FD lens seems stuck wide open on an adapter, that ring is usually the reason.
Nikon G and E lenses
Nikon’s G-type lenses have no aperture ring; the camera sets the aperture through a lever. E-type lenses have an electromagnetic diaphragm controlled digitally. On a plain adapter a G lens needs an adapter with its own aperture control, and an E lens cannot be stopped down at all. For these lenses, Nikon’s own FTZ on a Z body is the sensible route: see Nikon F lenses on Nikon Z.
Pentax DA lenses
Pentax’s DA lenses also dropped the aperture ring. Adapters sold for them (often labelled PK/DA) add an aperture control ring of their own that moves the lens’s lever. Without one, the lens stays at its default aperture.
Crop factor
A vintage lens gives the same field of view it always did only on a full-frame body. On APS-C, the frame is cropped: roughly 1.5× on Sony, Nikon and Fujifilm APS-C bodies and 1.6× on Canon’s. On Micro Four Thirds the crop factor is 2×. A 50 mm lens therefore frames like a 75 mm on APS-C and a 100 mm on Micro Four Thirds. That suits portrait lenses and teles; it makes wide-angle vintage lenses hard to use on small sensors. A focal reducer can undo much of it, at a cost: see speed boosters vs plain adapters.
Cheap adapters and good ones
A plain adapter is a machined spacer, and its one job is to be the right thickness. The differences between a cheap one and a good one are:
- Thickness. Too thick, and the lens cannot reach infinity focus: distant things are never sharp. Too thin, and the lens focuses past infinity, so the distance scale on the barrel is wrong and the infinity stop no longer helps you.
- Play. A loose bayonet lets the lens wobble or sit slightly tilted, which softens one side of the frame.
- Internal finish. A shiny interior can bounce light onto the sensor and reduce contrast. Better adapters have a matt or flocked inside.
- Fit. A tight or rough bayonet can mark lens mounts and camera mounts over time.
The fix for infinity problems is to test on arrival: focus on something several hundred metres away, at the infinity stop, with magnification on. If it is not sharp, return the adapter.
Leica M wide-angles
Leica M lenses adapt with room to spare, and there is nothing electronic to fail. The known issue is optical. Wide-angle M lenses were designed for film and send light towards the corners at a steep angle, which the thicker sensor stack of a digital camera handles poorly. The result is smeared corners and colour casts, strongest with very wide lenses. Nikon Z copes somewhat better than Sony E, but neither is immune.
For a starting point with M42: Search Amazon UK.
Where to go next
- The compatibility matrix shows which old mounts fit which bodies.
- The adapter index has a page for each pairing, with flange margins and recommended adapters.
- If you are tempted by adapted autofocus lenses instead, read autofocus with adapted lenses first.