PDA

View Full Version : High FPS and sync triggered flashes



Craig Parkes
11-15-2009, 04:55 PM
Here is something I have been thinking about in terms of the DSMC concept and it's use for extracting both stills and video, simultaneously.

Shoot at a very high frame rate, say 96FPS, but have a Flash that is sync'd to the camera and only set up to go off on say every 8th frame. That way you can get the amazing 'crisp' look of flash photography in your stills, which you extract from every 8th frame (so shooting at 12 FPS, pretty much the equivalent of most current stills and the fastest a photo type flash can go)

You then use only the odd non flash frames (1 and 3, 5 and 7 etc.) to derive your video footage, so that you are getting smooth motion at regular intervals.

This leaves you with a regular 48 FPS video. Now, I am not sure what the decay time is like on the Photographic flashes, so whether they will be visible across more than one frame at that frame rate. If so you still have wiggle room in this case to drop down to regular 24FPS by Just taking Frames 1, 5, 9, 13 etc and triggering the flash on frames 3, 11 etc giving you more time between the flash and the frame you are using.

Does this sound like a technique that could produce interesting, and usable results, or something that's just crazy.

I'm not so much thinking about use for dramatic stuff where you have actors at work (the flash would drive them crazy) but for getting dynamic footage of fashion models, cars, animals in action etc while still achieving that flash photography type effect maybe such a technique could work?

Frank Cueto
11-15-2009, 05:29 PM
Well, in theory sounds great, but I am sure actors would HATE it. ;-)

Bah, I should learn to finish reading posts ....

Charles Angus
11-15-2009, 10:00 PM
Problem is exposure difference between the flash and non-flash footage.

Craig Parkes
11-16-2009, 01:02 PM
Problem is exposure difference between the flash and non-flash footage.

Obviously this would be an issue, but with sufficient dynamic range and protecting for the highlights of the flash, (and noise reduction in post for video) will it possible to get a useful result?

Maybe it's an example of a situation where it would just be easier to have two cameras, but even if that was the case if you could have the flashes and the other (still camera) synched to the high FPS camera you wouldn't have to worry about flash photography disrupting your frame.

It's the high FPS and the synchronization of the flash with the recording film rate that is the key here, because you wouldn't have to worry about a flash interrupting frames in your video.