Methods of slo-mo

eqwalker

eqwalker

Active member
I wanted to get various opinions on how some of you do your slo-mo's. I know it depends on the circumstance, but for example how would you do this. If you wish to capture in 24p a runner that is running towards you and as he gets to you that is where you will go to slo-mo until he is just past you then back to normal as he runs away. Would you switch to a faster frame rate (another F setting) on the fly or is that even possible without giving you a glitch in the capture during the switch on the F dial? Or would you approach in a different manner? Opinions or suggestions?
 
I'd do it all in post. Some say to shoot 60i if you're going to slomo a shot, but my results have been mixed. In the movie Siren, we have a speed ramped shot and I just ended up using the 24p shot. The slo-mo looks marginal at best, but rendering the 60i at 24p for the normal speed looked bad also, so I elected to go with most of the shot looking normal, and the slo-mo looking ...odd. I did it in Vegas6 using the supersampling.
 
I've been fairly pleased with the 60i -> 24p slo-mo I've done. Just remember to shoot at 1/250 shutter speed or higher, if you can, for best results.
 
dougspice, did just have the settings programmed into one of the F settings and switched to it on the fly, or do you do it another way. How are you going from 24p to 60i and then back without interrupting your filming?
 
All in post. You're not going to find a good way to do that while recording. Even the HVX-200 won't do it. I'm not even sure if the Varicam does ramping while recording.

If you really want to do this sort of sophisticated speed ramping you need to find a camera that will handle more fps.
 
Okay. I didn't think that it could be done "on the fly" but I wanted to get feedback from others. I was just curious how they did some commercials where they slow down the action for a few seconds and they go back to normal speed without any jitter. Thanks for the comments.
 
I played around with this for grins one day in Premiere. I shot footage of a bunch of dimes being dropped on the carpet. Then took that into premiere and just keyframed where I wanted it to start slowing down, keyframed the point where I wanted the slowdown to remain constant - Then another keyframe at the end of that, and a final one that let it ramp back up from the previous keyframe.
 
The Varicam can ramp while recording. I'm not sure if the RCU is required for this but they had it on a shoot that I was on. It can ramp all through the frame rates. Someone also said it can use the shutter to compensate for the light loss/gain. They were using it without the compensation from 24 to 60 and back and the light loss was marginal anyways so it didn't draw much attention to itself. After all your changing the speed, people will notice that instead of a change of half a stop.
 
Oh, also. You could probably get a little slo-mo (about 15-20%) by shooting 30P and then editing it to a 24P timeline. Haven't tried this but it may work as long as you can remove the pulldown correctly.
 
I was just curious how they did some commercials where they slow down the action for a few seconds and they go back to normal speed without any jitter.
Click to expand...

Well, you can easily do that on a lot of film cameras, including some cheap 16s. I think the Arri 16S will do it? But at the DV level, no, no way. Best you could do is try something like Twixtor - which might actually end up looking great, but who knows?

thanks for the info, DPwannaB
 
Some of the newer Arri style film cameras have automatic ramping controls. They adjust the exposure during the ramp to keep things consistent. In some cases they shoot the full shot high speed and remove frames in video post.
 
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