All of the instructions I've read considering using an SLR on a tripod (especially during night shots) says to turn the SSS off during shooting.
I really don't have enough experience in night shots so I don't quite understand the in's and out's of it but why must you turn the SSS off when using a tripod? How will it affect the camera/images if you don't?
My understanding of this (from thinking about it for a while, rather than reading anything specific) is as follows;
When mounted on a good tripod, the camera should be stable, and so SSS should not be required.
If the system were perfect, it would detect no movement, and so hold the sensor steady (relative to the steady camera).
Unfortunately, electronics are not perfect, and even in high quality systems such as those used on DSLR, any circuit will have some
'noise' - when shooting hand-held, this will be (I assume) relatively insignificant compared to signals generated by camera movement - but when on a tripod, they will cause some small
movement of the sensor when not required - which will be prevented by switching the system off.