Rear lens caps · STL / 3MF
L-Mount rear lens cap to 3D print
A twist-on rear cap for L-Mount lenses that you print yourself. It locks like a camera bayonet, prints face down without supports, and can carry your focal length on the face, so you find the right lens in the case at a glance.
Locks like a bayonet
Four equal claws sit in the lens neck, so the cap goes on in any of four positions. Then turn clockwise (looking at the face) until the lugs run onto the stops.
Ramp and lock land
Each claw ramps down along the turn, then a nearly flat lock land holds the lug just before the stop. Resistance rises as you turn, and at the end the lug rests on a surface instead of an edge, so the cap sits firmly and wears less. Set just past the measured lug face like on our print-tested mounts; the free fit ring confirms it on your lens.
Made for FDM printing
Face down on the plate, no supports. Vertical teeth or flutes hide layer lines, a 45° foot chamfer hides elephant's foot, and the face gets the finish of your build plate.
Focal length, logo or mount code on the face
Optional: the focal length (zooms such as 24-70 too), your own logo or the mount code in big letters, as a flush inlay in a second colour or engraved 0.5 mm into the face if you print with one filament (tip: one wall on the first layer keeps it crisp). The mount code can also sit small above the focal length or logo. With a logo you print the same cap for every lens in your set. Inside, the mount code and the Focus Rings logo are engraved in the floor.
Fits
- L-Mount lenses from Leica, Sigma and Panasonic Lumix (L-Mount Alliance)
- Lenses from Samyang, Sirui, Viltrox, DJI and other L-Mount makers
- Weather-sealed lenses: the rim stays clear of the rubber seal around the mount
| Mount | L-Mount |
|---|---|
| Outside diameter | Ø60.8 mm |
| Height | 14.7 mm · Deep 20.7 mm |
| Room for the rear element | 12 mm below the rim; Deep: 18 mm |
| Grip | Module 0.8 gear (74 teeth) or flutes |
| Print orientation | Face down, no supports |
| Print time (slicer estimate) | about 33 min, about 12 g PLA |
| Fit test ring | Free, about 16 min |
| Files | 3MF (body + face inlay as one object), aligned STLs, printing guide |
Print times are Bambu Studio estimates for an X1C with a 0.4 mm nozzle and 0.20 mm layers. Not every lens has been tested: print the free fit test ring first.
Print and fit
- Print the free fit test ring in the generator. It is the bayonet zone only and done in minutes.
- Put the lens lugs into the gaps and turn clockwise (looking at the face) until it stops. It should turn smoothly and sit firmly.
- Print the cap face down on the build plate, no supports. Two-colour faces: keep body and inlay as one object and give each part a filament.
Questions
Which lenses does the L-Mount rear cap fit?
L-Mount lenses from Leica, Sigma and Panasonic Lumix (L-Mount Alliance); Lenses from Samyang, Sirui, Viltrox, DJI and other L-Mount makers; Weather-sealed lenses: the rim stays clear of the rubber seal around the mount. Room for the rear element: 12 mm below the rim; Deep: 18 mm.
Has this L-Mount rear cap been tested on a lens?
Not yet on a L-Mount lens. The bayonet is measured from parts that fit real lenses and cameras, the lock is set just past the measured lug face like on our print-tested mounts, and every file passes a layer-by-layer support check. Print the free fit test ring first: it is the bayonet zone only, done in minutes, and shows on your lens whether the cap will turn on and lock.
Does it need supports?
No. The cap prints face down on the build plate. Every overhang is at most 50°, and the claws have sloped undersides that build up layer by layer.
Which filament should I use?
Rings without clamps and lens caps: PLA or PETG, 0.4 mm nozzle, 0.20 mm layers, your usual walls. PETG is a little tougher if the cap lives in a bag.
Why gear teeth on a rear cap?
They are the same module 0.8 teeth as our focus rings, so the cap matches your follow focus gear and grips well with gloves. The vertical teeth also hide layer lines. Prefer something smoother? Pick the flutes grip.
What does it cost?
One price per file, focal length and AirTag pocket included if you want them. The fit test ring is always free.