I bought a godox 100W and it doesnt't flicker however the lighting is so dark still. I am not sure how many Godox I need to buy until the lighting is good like my slr which lighting is perfect every time. With good lighting comes good quality slo motion videos. With not so good lighting, the quality is not good. Chronus is a very expensive hobby.
Depends mostly on how big of a Scene you want to Light with that one 100W LED-Light. Also depends a Lot on your exposure-Time /Framerate.
If you want to Light some small part of your Desk and take some Macro-Shots in Slow-Motion, it should be Plenty of Light for most of the time.
If you want to Light a football-Field (realy stupid big example) with that one 100W LED you will run into problems, even with Modern DSLR´s for normal Video.
The closer you (can) place your Light to the Object, you want to Light, the brighter it will be.
And if you have a smaller Area to Light up, it will also be Brighter.
If you want to Light something of the size of an normal Room you will need quite some Light for that, even at "just" 1500fps.
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I did hear a Fimmaker once say, that you should invest as much money into Lighting than you spend on the Camera you are Using, if you want a realy good result.
And i think, that especialy for Highspeed-Video it is mostly true. An exception might be, if you are able to Use Sunlight (and maybe reflectors) all the time when you are Filming.