Articles on Lens Mount

Why you can't put mirrorless lenses on a DSLR

Fri, 18 Sep 2026 09:20:00 +0100

A mirrorless lens cannot be adapted to a DSLR because it would sit too far from the sensor. Mirrorless lenses are designed to sit between 16.0 and 20.0 mm from the sensor; DSLR mounts hold the lens between 38.67 mm (Four Thirds) and 46.5 mm (Nikon F) away to make room for the mirror. An adapter can only add distance, never remove it, so the lens would behave like it was on an extension tube: it could focus close up but never at infinity. Fixing that needs corrective glass in the adapter, and even then most mirrorless lenses have no aperture ring or mechanical controls a DSLR could operate.

Using vintage manual lenses on a mirrorless camera

Thu, 17 Sep 2026 11:10:00 +0100

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.

Speed boosters vs plain adapters: what the glass does

Wed, 16 Sep 2026 09:45:00 +0100

A plain adapter is an empty tube that holds a lens at the right distance from the sensor; it changes nothing about the image. A speed booster (the generic name is focal reducer) is an adapter with a lens group inside that shrinks the lens’s image circle onto a smaller sensor. That makes the field of view wider and the effective aperture brighter, typically by about one stop for a 0.71× reducer. It only works when adapting a lens made for a larger format onto a smaller sensor.

Autofocus with adapted lenses: what actually works

Tue, 15 Sep 2026 10:30:00 +0100

Autofocus through an adapter works best when one company made the lens, the adapter and the camera: Canon’s EF-EOS R and Nikon’s FTZ pass autofocus through much as a native body would. Third-party “smart” adapters that translate one maker’s lens protocol into another’s usually manage reliable single-shot AF, but continuous tracking and eye detection vary lens by lens. Older lenses that rely on a focus motor in the camera body often will not autofocus at all.

Canon EF-M is discontinued: what to do with your lenses

Mon, 14 Sep 2026 09:05:00 +0100

Canon discontinued the EOS M system in October 2023, when Canon Japan listed every EOS M camera as a discontinued product. There was no press release. There will be no new EF-M bodies or lenses. The lenses cannot move to Canon’s RF mount either: EF-M’s flange focal distance is 18.00 mm and RF’s is 20.00 mm, so an EF-M lens would have to sit 2 mm inside an RF camera, which no adapter can arrange. That leaves four honest options: keep shooting, sell, switch to RF and replace the lenses, or build around EF lenses, which do carry over.

Fujifilm G mount vs X mount: what's the difference?

Sat, 12 Sep 2026 11:40:00 +0100

Fujifilm X mount is the company’s APS-C mirrorless system, with a 17.70 mm flange focal distance. Fujifilm G mount is its medium-format GFX system, with a 26.70 mm flange distance and a sensor about four times the area. The two are completely separate: an XF or XC lens does not fit a GFX body, a GF lens does not fit an X body, and Fujifilm makes no adapter between them.

What is the L-Mount Alliance, and which lenses fit L-Mount?

Thu, 10 Sep 2026 09:15:00 +0100

The L-Mount Alliance is an agreement that lets several manufacturers build cameras and lenses on the same lens mount, originally designed by Leica. It was announced by Leica, Panasonic and Sigma on 25 September 2018. As of September 2026 it has eleven members. Any L-Mount lens fits any L-Mount body natively, with full electronic communication, whichever member made each part.

That is unusual. Most mounts belong to one camera maker, which decides who else may build for it.

Flange focal distance: why some lenses adapt and others never do

Tue, 08 Sep 2026 10:20:00 +0100

Flange focal distance (FFD) is the gap between the lens mount’s seating face and the sensor. A lens can be adapted to a camera with a plain, glassless adapter only if the lens’s mount has a longer flange distance than the body’s, by enough to fit an adapter into the difference. This site’s compatibility matrix uses 2 mm as a conservative minimum, although a few specialist adapters manage with less. For the search that brings many people here: the Leica M flange focal distance is 27.80 mm.