A lens mount is the physical and electronic connection between a camera and a lens. Two lenses from the same brand can use completely different mounts and be incompatible without an adapter.
Common examples
- Canon RF and RF-S lenses use the RF mount.
- Canon EF and EF-S DSLR lenses use the EF mount family.
- Canon EF-M lenses use the discontinued EOS M mount and do not fit RF cameras.
- Sony APS-C E lenses and full-frame FE lenses share the Sony E-mount.
- Nikon Z lenses use the Nikon Z mount.
- Micro Four Thirds lenses use the Micro Four Thirds mount shared by several manufacturers.
What does an adapter do?
An adapter can place a lens at the correct distance from the sensor and, in some cases, preserve autofocus, aperture control, stabilization, or lens data. Compatibility depends on the exact camera, lens, and adapter.
Why can one direction work but not the reverse?
Lens mounts have different flange distances and throat dimensions. A DSLR lens can often be adapted to a mirrorless camera because the mirrorless body leaves extra physical space for an adapter. The reverse can be impossible because there is no room to position the lens correctly.
Does a lens being physically mountable guarantee full function?
No. Autofocus, continuous autofocus, eye detection, stabilization, aperture control, EXIF data, burst speed, and video behavior can all vary.
Always check the exact model names
Compatibility questions are one of the main reasons product-specific pages exist on this site. A single letter in a product name can identify a different mount, generation, filter size, or accessory system.