Sony A1 has a Sony E lens mount and currently there are 172 native lenses available for this mount.
A1 also has a sensor based image stabilization system which means that all of these lenses will be stabilized when used on A1.
Since Sony A1 has a Full frame sensor, it has a focal length multiplier of 1x so lenses will provide their original focal length on A1.
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Sony A1 Lenses with Image Stabilization
Sony A1 Lenses with Weather Sealings