Video light questions - how bright? What color?

[tamas970]

I am in the process of designing and diy-ing a pair of video lights. Initially I'll shoot with an Olympus E-PL5, later I might upgrade.
I would also use the lights for stills.

So far what I learned: the brighter the better. Haven't seen a (not insanely priced) light, that illuminates a large target - e.g. wrack enough for iso200@f/8,@1/200sec. Not even close...

Thus the first question, how many lumens shall I bring underwater? Drawbacks of too many might be: #1: spooking all critters or worse, blinding them, #2: too much backscatter - even if the lights sit on long arms. #3: battery weight (I have to fly to get some diving...)

To me, it looks to be a trade-off, and need some advice to find the sweet spot. (where I can take stills f/8, 1/100sec - but I wont fry the fish around).

Other question is the color temperature: water absorbs red rapidly, thus I am considering 4300k. Unfortunately high power efficiency LED-s are not really available for this range, only HIDs.

Technology-wise car/truck HID kits are the highest in my list, especially the 55-75W models. I saw here and there variable power units mentioned, but hardly available. The best would be of course a 24-80W variable ballast...

 

[Interceptor121]

Lights for still work up to 1/125 shutter then blur
For video a minimum set is twin 800 lumens if you have a camera with f/2 or brighter
Lights should be dimmable and work in flood spot so you don't need a torch on night dives
Of course the more lumens the better but with two twin 1200 you manage to scare fish off even in daylight I cannot imagine what it means to be illuminated by two 4000 definitely at macro distance you would fry the fish

 

[tamas970]

For macro distance I guess I have to get a LED setup, HID is way too bright.

 

[dpaustex]

Your question is a bit too broad, not knowing much about your camera. I lot of video quality is determined by how fast your setup can write to disk/card, and how fast your storage actually is (UDMA 7 or higher?).

For a DIY, I'd suggest a pair of UK Light Cannons. You can put diffusers on the lens. Don't have one? Make one from a milk jug, and put inside the lens (or make "ears" on the plastic, and put on the outside of the lens and hold in place with elastic cord). A lot of people are moving away from these lights, and going to LED (as you pointed out, their light isn't very good for video), so you can pick them up pretty cheap (about $140/each brand new).

There is no such thing as too much light, as you can always tone it down with diffusers, etc. (you can stack them, BTW).

Have fun.

 

[matdiver]

Hey tamas970,
I've been using a halogen Kowalski Maxum1250 for years now for video, and for me it's just perfect. Super bright lights just annoy the marine life. Can you imagine a turtle hanging around for 10 seconds with 4000 lumens in its eyes? If you're filming deep wrecks in Swiss lakes, then maybe OK..., but for warm water diving I'd suggest you look at halogens for their CRI of 100 (Bing "colour rendering index", if you're interested - but it's very technical, and a lot of the info is inconsistent). True, halogens don't pentrate as far in water as LEDs, but they give a lovely warm colour which means little or no correction in post. My Kowalski pushes out 1600 lumens max, but for night dives I usually have it on half power or less. Kowalski use a normal 50W Osram halogen capsule style bulb, rated at 12v, which they "overdrive" at 14v. Kowalski say in their product info. that Osram bulbs are the only ones that you can do this with. You would need to make a flood reflector, otherwise all the rest of your work would be a waste of time. The flood reflector on the Kowalski is so wide, that I only use one torch, which saves on weight when travelling. Li-ion batteries would be the way to go.
There's a 100W version of the bulb here:
12V 100W REPLACEMENT BULB: Amazon.co.uk: Lighting
For a few Swiss francs, might be worth trying.

As I'm sure you know, any subject more than about 2 metres away won't be caught by pretty much whatever light you build, but that's where filters and manual white balance come in....
Good luck with your project.
Matthew

 

[tamas970]

Hey tamas970,
I've been using a halogen Kowalski Maxum1250 for years now for video, and for me it's just perfect. Super bright lights just annoy the marine life. Can you imagine a turtle hanging around for 10 seconds with 4000 lumens in its eyes? ...

Definitely NOT I would be annoyed as well. Not to mention bigger predators, that may think you to be some exotic meal...

 

[Interceptor121]

I agree with 1200 lumens twin however halogen lights are heavy as am sure those kovalski are
The reality is LED are colder but very light and easy to handle you can warm the up with filters but I have found that unless you blast fish in the face sola 1200 work very well as you can reduce to 600 and 300 with the control which is excellent
2000-4000 lumens are more for wrecks or other landscapes to be honest it is a lot of light

 

[tamas970]

That's why I am fun of HID until someone shows me a real 10W, 1000 lumens 4300k LED.
Using an orange filter on a blue LED is VERY counterproductive.
You may easily cut 75% of the total power if you want accurate colors. Just add the wast
blue excess (color temp. 7k?) and 1m target distance to the equation (=for correct colors you have to
push the color temperature down to ~4000K).


Indeed, HID is perishable. However, I can live with 100+hours bulb life, this means 1 bulb for me each year (costs 50$ at most if you have to replace the ballast as well).

I agree with 1200 lumens twin however halogen lights are heavy as am sure those kovalski are
The reality is LED are colder but very light and easy to handle you can warm the up with filters but I have found that unless you blast fish in the face sola 1200 work very well as you can reduce to 600 and 300 with the control which is excellent
2000-4000 lumens are more for wrecks or other landscapes to be honest it is a lot of light

Continuing my homework, I think the gut of the HID flashlights (variable ballast+bulb, 35-75W) available on e-bay for ~100 bucks will be a good starting point (4300k, 85/65/45 or 75/55/35 ballast+bulb kit only costs ~30$). I concluded, I might need the extreme power sometimes - titanic-size wracks, daylight compensation(!!) but the low setting is a must, if I nightdive in a team or the critters are shy.

Anyway, regarding the reaction of sealife: a blue/cold white light is probably much more disturbing for them, than a warm beam. I remember visiting fairy penguins when they returned to their burrows in the night - they were absolutely not afraid of our red flashlights.

 

[Interceptor121]

There are few legends around the fact fish don't see red light, it is not true they don't see it is red but they still see some luminance less annoying but still annoying
So if you pump enough light sufficient for you to shoot usually the fish gets scared either this is 6000,4000,2000 K is just a detail it will get scared light is not invisible

 

[tamas970]

You are right, they do. Although, most species are more sensitive to blue/green (those LEDs...) Googling fish color vision there are some useful info.

Anyway, variable power is a must and doesn't seem to be impossible even in a DIY project. LOT of power (10+k Lumens) is also necessary sometimes.

There are few legends around the fact fish don't see red light, it is not true they don't see it is red but they still see some luminance less annoying but still annoying
So if you pump enough light sufficient for you to shoot usually the fish gets scared either this is 6000,4000,2000 K is just a detail it will get scared light is not invisible