I'm thinking of doing some Slo Mo work with A1U and was wondering at just what point does the rolling shutter effect kick in as far as shutter speeds and movement go.
For example, if I lock the fps down to 120 and have little if any camera movement (even though there is fast movement in the frame)... is it safe?

I know DSE has done a lot of work with the A1U and is extremely knowledgeable about the myths and realities regarding the rolling shutter effect, so I'm hoping he will chime in here.

The effect is always there. It just shows up more with higher shutter speeds because there is no motion blur to hide the effect. Is it usuable will depend on the application.

Well I'm trying to get some basic useable parameters, as I have been thinking of doing some slo mo (not much but some with the A1U).

Parameters? Well...it takes for the cmos to scan the image 1/60th of a second. The bottom part is 1/60th of a second later than the top.

Slow-mo work is trickier because a 50% slowmo will show the effect twice as hard. But it is possible to do slowmo shots if you just limit the movement of the camera itself.

I've done slowmo work with the HC1 and...well you just have to see it for yourself, it's very hard to describe the effect. You can make shots terrible or they can look very nice with no visible rolling shutter depending on how you shoot it. No rapid camera motions. That's a must for slow-mo work.

Here's a clip with some slow-motion shots with the hc1.

http://www.hmcindie.com/movies/Taikki%20setti%20hd%20quality.wmv

Nice.
Well with the shutter speed set to 60, I have seen no evidence of the rolling shutter effect whatsoever. Maybe because I'm not a big fan of whip pans?