Different brands of SLR lens mounts are different and are not compatible with each other.
Take the three common SLR brands as examples:
1. Canon EF mount
2. Nikon F mount
3. Sony A mount
As you can see, different brands of mounts have different contact positions, apertures, and notch positions, and the lenses cannot be universal.
In addition, the focus points of different brands of lenses are designed for the flange distance of that brand. Even if they are installed, they will not be able to achieve focus.
Of course, there are adapter rings currently on sale that can make lens mounts of different brands compatible with each other. However, it will also cause problems with focal length, aperture, and focus accuracy. Some adapter rings can only support Manual focus.
Extended information
Basic knowledge of SLR lenses
Basically includes information such as lens attributes, focal length parameters, aperture parameters, and characteristics.
1. Lens attributes: usually indicates whether the lens is AF mount or EF mount, and usually also includes some identification of lens categories.
2. Focal length parameter: Indicates the focal length range of the lens, in mm.
3. Aperture parameter: Indicates the maximum aperture coefficient of the lens. Some lenses also indicate the minimum aperture coefficient of the lens.