Sony A100 has a Sony/Minolta Alpha lens mount and currently there are 143 native lenses available for this mount.
The latest released lenses that are compatible with the A100 are the Lensbaby Sol 45 DSLR, the Venus 105mm F2 and the Lensbaby Burnside 35.
A100 also has a sensor based image stabilization system which means that all of these lenses will be stabilized when used on the A100.
Since Sony A100 has a APS-C sensor, it has a focal length multiplier of 1.5× so you have to multiply lenses original focal length with this multiplier to find the Full Frame equivalent focal length of the lens when mounted on A100.
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Sony A100 Lenses with Image Stabilization
Sony A100 Lenses with Weather Sealings