A lens mount is the connection between body and lens. Choosing a camera means choosing a mount, and the mount decides which lenses you can use for years to come.
The main mounts today
- Sony E: the widest choice of third-party lenses from Sigma, Tamron, Samyang and Viltrox.
- Canon RF: excellent Canon lenses; third-party autofocus lenses are growing but still limited, especially for full frame.
- Nikon Z: strong Nikon lenses plus Tamron, Sigma and Viltrox options.
- Fujifilm X: APS-C only, with good Fujifilm, Sigma, Tamron and Viltrox lenses.
- L-Mount: shared by Leica, Panasonic and Sigma, among others.
- Micro Four Thirds: shared by OM System and Panasonic, with many small lenses.
Adapting older lenses
Mirrorless mounts sit close to the sensor, so most older lenses can be adapted. Canon's EF-EOS R adapter and Nikon's FTZ II keep full autofocus with most DSLR lenses from the same brand. Adapting across brands, such as Canon EF to Sony E, is possible with adapters from Metabones or Sigma, with some autofocus limits.
Crop and full-frame lenses
APS-C lenses on a full-frame body of the same mount usually work in a cropped mode at lower resolution. Full-frame lenses work on APS-C bodies with the crop factor applied.