Sony ILCE-7S - Manual (Page 42)

Be sure to hold the lens straight when attaching it.
Note
Do not press the lens release button when attaching a lens.
Do not use force when attaching a lens.
A Mount Adaptor (sold separately) is required to use an A-mount lens (sold separately).
When using the Mount Adaptor, refer to the operating manual supplied with the Mount
Adaptor.
If you want to shoot full-frame images, use a full-frame size compatible lens.
When you use a lens with a tripod socket, attach a tripod to the tripod socket of the lens to
help balance the weight of the lens.
When carrying the camera with a lens attached, hold both the camera and the lens firmly.
Do not hold the part of the lens that is extended for zoom or focus adjustment.
[21] How to Use Preparing the camera Attaching a lens
Removing the lens
Set the power switch of the camera to OFF before you remove the lens.
1. Keep pressing the lens release button (A) and turn the lens in the direction of the arrow
until it stops.
2. Attach the lens caps to the front and rear of the lens and the body cap to the camera.