Lets talk lumens!

Looking to get some video lights soon but unsure where to start. Camera is a GH4 with 7-14mm lens. What are some recommendations? I know that the lights would depend on the project, so I'm just looking for some generalized/flexible suggestions for now. I don't want corded lights as the rig will be scooter mounted. If I was choosing between 6k lumen and 10k lumen lights, other than physical size considerations, would there be any reason to buy the 6k light over the 10k light?

I would suspect that another consideration might be price...

I would suspect that another consideration might be price...

Let's set price aside initially. There is fair bit of difference in prices even among various brands of lights of similar claimed lumen output.

Pretty sure the answer will wind up being that you can't have too much light.

CRI (colour rendering Index), lots of power yes but must be dimmable and non- flickering or colour shifting. Sensible battery system for travel and weight. Variable beam adjustment.

Just my two cents

CRI (colour rendering Index), lots of power yes but must be dimmable and non- flickering or colour shifting. Sensible battery system for travel and weight. Variable beam adjustment.

 

Just my two cents

Hmm, variable beam adjustment, as in beam angle?

Yes. You will need less angle of beam in certain situations. Beam should be even in either spot, medium beam or wide beam. To do so correctly in a powerful light would need some sort of lens/ diffuser.

One thing to note is that better powerful light heads do not use array of power LEDs that is spread out in the light because that would produce multiple shadows.

Two cents worth...

Don't get hung up on Lumens, you really want to be looking at the Lux / Candle Power

This is how bright a m2 area is from a meter away. This gives you a better understanding how powerful your lights will be, obviously this is directly related to the beam angle as a 10,000lm light with a 8 degree beam will be a lot brighter than a 10,000lm light with a 90 degree beam, however for video having a tight beam is not the desired configuration, as you ideally want the whole scene to be lit. So you have to trade the power with coverage...

For video, you need a nice wide beam, high CRI rating and a nice kelvin temp too.

If you want the crème de la crème have a look at the Keldan Video8 lights. Loads of power, long burn times, CRI of 98 - the list goes on. However so does the price...

Lumens and lux are related and in any case you can't compare two lights unless they have the same beam angle. For example a 1200 lumens light with 80 degrees coverage will feel much stronger than another 1200 lumens light with 120 angle. My advice would be first to work out what coverage you need depending on the lens you have and the subject and then work out what intensity you require. Your GH4 has around 100 degrees at 4K if you wanted something to cover wide angle you would need two lights with more than 100 degrees coverage. Say that you find a 120 degrees light you are looking at 3000+ in water if you want to cover a surface at 1 meter distance. Less than this intensity won't be worth it

I guess that you won't do macro with a camera mounted on a scooter so i would take the most powerful with the widest beam.

If you should use the light in a cave or at night then 6000 lumen can be enough, but under daylight situations it is not enough for wide angle.

My 2 Mangrove 120° 4000 lumen LED video light illuminate at daylight and 12 meters deep in clear water approx 50-60 centimeters in front of them, not more.

My new FIX Neos 2500 video light about 30-40 centimeters, not more.

Yes, it would be better if manufacturers would show the lux instead of lumen, but unfortunately the don't ...

I personally would go with the most powerful ones i can afford as long as i can dim them and they have a CRI above 85/90

Chris

P.S. Have a look here:
http://wetpixel.com/forums/index.php?showtopic=53014
http://wetpixel.com/forums/index.php?showtopic=52602
http://wetpixel.com/forums/index.php?showtopic=51659

A studio scene is set at 1000 Liz however an overcast day is also sets at 1000 lux. Your mangrove lights at half meter give 5000 lux each so you will possibly see something. In a bright day on a sandy bottom probably absolutely nothing as the environment is already brighter than the light. That's why filters exist. If you are in a cave or very deep the light will indeed be useful. The key is to find lenses that perform well around f/4 and shoot at slow shutter such as 1/50 so that you don't have to bump the ISO too high. But no artificial light can beat the sun I guess and also fish don't like it so only good for wrecks

I think many wide angle subjects don't like strong light and so are my diving partners/buddies.

Well, I've decided on a set Keldan Video/Luna 8 lights. It was about the best combination of price, quality, size and power I could afford (barely!). Now I just need to get the camera rig neutral and wait for my scooter mount to arrive. Will have to balance arm length vs drag as well. Looking forward to trying this out!

Congratulations!
The Keldan lights are excellent lights,
probably one of the best and that BBC use them for underwater footage is a good sign!

Have fun with them!
Chris

Good choice!

Remember the camera and housing will always be an upgrade target, but the accessories and ancillary parts will stick around with you for a while - so best to buy the best you can at the beginning.

..awaiting your first video!