Slow motion lighting
Posted 13 May 2009 - 05:41 PM
Posted 13 May 2009 - 06:15 PM
Posted 13 May 2009 - 06:28 PM
Do you mean "economical" in the monetary sense, or power-consumption sense?
I'm pretty sure that way up in those kind of framerates, large tungsten units are the only choice. There are a few people here (Kevin Zanit being one of them) that do a lot of high-speed work and they can tell you for sure, but I think you're looking at 10Ks. Even 5Ks probably flicker at 2000fps.
Edited by Chris Keth, 13 May 2009 - 06:30 PM.
Posted 13 May 2009 - 06:51 PM
Posted 13 May 2009 - 06:54 PM
The short answer is the cheapest light source for these frame rates would be the sun.
In a studio setting you need to use either Tungsten lights that are 5k or bigger. Smaller sources will flicker. You can use HMIs. Personally, I have had mixed experiences with HMIs. Sometimes you will get flicker/ arc wonder (these are two different things, but both can happen at these frame rates). Lightning Strikes Softsuns have worked very well though (50k and 100k units).
What 16mm camera would be using that could shoot at 2000fps out of curiosity? Most film cameras will be a bit more forgiving about flicker because there is no pin registration, etc which means there are typically so many other problems with the image you don't notice flicker.
Posted 13 May 2009 - 07:16 PM
Posted 13 May 2009 - 11:34 PM
Thanks for the info I'll find a 10k after testing it useing the sun.
Posted 14 May 2009 - 06:34 AM
FYI a number of 16mm rotary prism cameras go to 10,000pps- the Hitachi, the NAC E10, the Fastax 2- and the various Fastax 1s with no speed regulation will manage about 6000.
With pin registration you're really limited to the Locam or the 1PL at 500.
Of course you need double-perf film.
Posted 14 May 2009 - 04:30 PM
Posted 14 May 2009 - 04:36 PM
In a studio setting you need to use either Tungsten lights that are 5k or bigger. Smaller sources will flicker.
Just out of curiosity, why will sources smaller than 5k flicker?
Posted 14 May 2009 - 06:21 PM
The flicker with smaller tungsten units is because on AC power the 60Hz cycle causes the filament to heat up and cool down. With smaller globes the filaments are small and thus cool down much quicker, so you actually see the filament turning on and off at those frame rates. With bigger globes (5k and up), the filament is so big that it cools down much slower and thus appears continuously on in spite of heating up and cooling down at 60Hz.
On DC power none of this is an issue.
Posted 15 May 2009 - 01:18 PM
Posted 15 May 2009 - 01:35 PM
Drum cameras ran up to a couple of million fps, although with stationary film and one lens per frame, the image being reflected off a mirror spun up to a similar speed with compressed air.
That will teach me to post before looking it up. I checked out Photosonics site and, man, 16mm cameras can go really fast! Never would have guessed!
The practical limit for moving film is really about 10,000 fps, or 20,000 using a half-height frame. 16mm. being less massive will go quicker. The limiting factor is really how fast you can run up to speed, and how much film is left when you've done it. Even at 5,000fps which is really the limit of my experience, it takes about as long to run a 400' spool as to say 'high speed cine is very expensive'.