50P and 60P are available frame rates in 720P.

A good line Andy, a good line.

Yes 720P50. No interlaced rubbish (IMO progressive is no much better) and enough frames to do excellent slo-mo. 50% slo-mo is 25P which some are advocating shooting at. Why? Shoot 50P and you have much more to play with.

Guys,
Unless you have HVX200 or EX1 which let you do 60p the slow mo is only smooth in 60i which you have to de-interlace. Or put it on 30p, like on mine XHA1, and slow it down only 80% to work in 24p timeline. The cinema effect is only achieved in 24p timeline, which most of us want. My question is, how do you switch between the speeds. When do you know you won't need a slow-mo and want to record only normal speed. In other words, do you switch between frame rate, let say 24p and 30p, or 60i during wedding?

True, the cinema look is 24 or 25P, but do you want to shoot weddings in 24P? I shot a wedding last year in 25P ( PAL land) and had a complaint that the fotage "looked jittery". Of course there was nothng I could do about it after the event.

Most brides don't care for "the cinema look". They want to see nice video of their wedding.

Shooting slo-mo in HDV means the resolution of the pictures is reduced (though not in the EX1) though for some situations that don't need the full HDV quality this is not a problem. Unfortunately audio cannot be recorded while in this slo-mo mode. That being so I will say that I use the softening effect of post-production slow-motion to good effect in my wedding films and there's no way round it at my price level.

When I get the groom to twirl his bride around I'll often add to the softening effect of the slo-mo by intentionally adding motion blur (a Canopus real-time filter). On top of that I can cut and paste the clip to the video track above, reduce its transparency and moving it out of sync by a couple of frames - all adding to the romantic softening.

Another effective technique is to vary the rate of slow-motion, and this is best decided upon during the edit. A twirl looks very effective if it starts off at normal speed, sine waves smoothly down to 20% and then back up to normal speed as her feet touch down. Shooting everything normally lets you decide later what scenes should be have their speed varied and by what amount, and for run 'n' gun shooting this is really the only option. You also get to capture the sounds made at the time - quite important I find.

tom.

Tom, good points but by shooting 50P at nrmal speed, you can do slo-mo easily in post without jitter, and still have the audio. (though obviously if you slow the footage by 50% the sound will be as well so it needs to be adjusted)

If you shoot at 24P there is no way on earth you can use it for slo-mo. 50% will be 12 FPS, which will look dreadful.

I don't ever do slo-mo in camera at a wedding. There's no need to with 50P anyway.