Chronos > Chronos User Discussion
Let's talk lighting
jasonfish:
I've been using one of the Stratus LEDs with a benchtop power supply. It's plenty bright, but a real hassle to power. My PS only supplies 5.1A, which is barely enough. The other option is a pre-made 24v 7A wall wart, but I'd probably have to order 5 or 6 of the things to find one that doesn't induce flicker.
They have a wall wart on their site, but it's not yet available for sale. In the meantime they suggest a 6s hobby LiPo, but that means buying another charger, not to mention the need to recharge every hour.
I'm seriously considering that Godox.
thebishop:
--- Quote from: tesla500 on September 15, 2017, 02:00:15 PM ---As a rough estimate, for a color camera, you'll need about 7 lux per fps at f/2 and 360 degree shutter.
So at 4000fps, you'd need about 4000fps * 7 = 28,000 lux. If you want to run f/4, you'll need 4x as much light, so 110,000 lux which is about noon day sunlight
I'm afraid you'll need far more light than those Manfrotto lights will provide, unless you're putting them right next to the subject. At 1m (3') distance you'd need 18 of those lights for f/2 4000fps
--- End quote ---
Thanks a lot for that estimate, much appreciated!
I will try to change my preorder to a monochrome version then to make it easier to light the scene, then I can stop caring about CRI too, perhaps there are some cheaper/brighter light sources if that is a non-issue, will need to google a bit...
I would like to run with less than 360 shutter too (I want to use the camera for archery shot analysis primarily, want to see the arrow clearly as it leaves the bow).
I can put the lights slightly less than 1m from the archer, but not closer (need some safety distance).
Perhaps it is ok with som gain as well, I haven't seen enough comparable footage with/without gain yet to know if it is ok.
thebishop:
So looking at the Godox with the NG-10X fresnel attachment - according to an Amazon reviewer that gave about 30,000lux @ 1m, so two of those and going black-white should make f/4@4kfps more or less in range (preferably three to get down from 360 shutter...). Will continue to loo a bit more... :-)
sam:
Inspired by tesla500, I rigged up lights with the Chanzon 100W led modules ( here now, but this link moves around...).
I drive each of them with one of these constant current boost converters each. This is probably overkill, but these are so cheap... I mount the LEDs to the front of a cpu water cooling block, and the drivers to the back. Right now I'm driving 3x100W LEDs, a water pump, and fan for the radiator with a 500W ATX power supply.
Overall, this is ~25k lumens for ~$100. It stays plenty cool, and works well, but I think there's lots of room for improvement. And of course, now that my camera has arrived, it doesn't seem bright enough any more!
wilheldp:
--- Quote from: thebishop on September 15, 2017, 11:18:19 PM ---So looking at the Godox with the NG-10X fresnel attachment - according to an Amazon reviewer that gave about 30,000lux @ 1m, so two of those and going black-white should make f/4@4kfps more or less in range (preferably three to get down from 360 shutter...). Will continue to loo a bit more... :-)
--- End quote ---
I bought that exact setup. I haven't had a chance to use it with the camera yet (mine will hopefully ship next week), but I did some testing on the light and lens. http://forum.krontech.ca/index.php?topic=5.msg364#msg364
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