Video Lights with Red LEDs

[james_bond_007]

I am hoping someone would explain the use of the Red LEDs in some of the video lights that are being offered.

Here is my understanding...(please tell me where I start to stray)
I know that as you go deeper, the colors from the ambient light (aka the sunshine), starting with the lower frequencies like Red, start to be filtered out by the water column.
For example at 40' deep, reds will be greatly attenuated, oranges a bit too but not as much as reds, then yellows etc.

Using a red filter in this case, attenuates all the other colors, except red, and provides a better color balance image, at the expense of intensity. That is, the picture may be more balanced, but it is not as bright as an unfiltered image.

But when using a video light (essentially a White Light), the subject might be 5' or so away and maybe only a few feet most of the time. Thus if the video light can provide enough white light to illuminate the subject, the camera-to-subject distance has the effect of only filtering the reds for that short distance, not the 50' depth.
There will not be very much attenuation for a subject-to-camera distance of a few feet. The white lite should provide a fairly uniform color response from the subject.

So, what does the use of red LEDs in a video light really do for me ?
My only guess is that it is trying to act as a sort of anti-filter and trying to amplify the reds to balance out with the rest of the colors.

But it woulds seem that a better solution would be to just use white light and intensify all the colors and keep the subject-to-camera distance a reasonable value for the particular video light. In that manner, one also gets corrected Oranges, Yellows etc. , which are also being attenuated, albeit to lesser degrees than the reds.

I look forward to your comments.

 

[tbone1004]

it acts as an active filter limiting the loss of light to the lens from a true filter, and does so without blinding the subjects you are shooting at. Similar reason to why many camping headlamps have a red light to protect your night vision

 

[Stoo]

I use a small video light as a focus light for still photography. It's believed that the critters can't see the red light well, so it's easier to sneak up on them for macro shots. In my experience, it works pretty well, although you still need to move gingerly.

A few weeks ago, i was asked to photograph the placement of a memorial plaque for a friend who died while diving in Tobermory. The chosen location for the plaque was inside the engine room of his favorite wreck... at night. So it was a little on the dark side. I didn't want to use the video lights on on my Ikelight strobes since there was a lot of rust and silt in the water, from three guys working with tools. I used the red LED on my focus light and it worked well keeping the backscatter to a minimum.

 

[Hatul]

I have a Big Blue video light with the red light option for use with GoPro and can see the logic when it's used as a focus light for a still camera with a strobe, but I don't see any use with a video camera.

 

[Schwob]

I am fairly new to all this, so take it with a grain of salt - I am sort of telling and asking here at the same time:
I use mine as focus light when taking stills and using a flash, I also used them during night dives just to sneak up on things and to observe w/o being that disturbing and it seems to make quite a difference, because when I then switch to white, many fish (and e.g. octopus too) seem to want to dissapear. Others come to try to hunt in the light. This summer I watched a blue spotted stingray for quite a while doing his strange ondulations in the sand under red light. I was pretty darn close to see well and in detail and when I decided to see that even better yet and switched to white, he (she?) didn't like it at all. popped up a couple of feet and turned towards me, practically on me. I quickly turned to move a way w/o getting closeer to the tail, regretting to have him/her disturbed that much and wondering if it's just a reaction to the light or if he/she's trying to get me... Anyway as I turn, three lionfish are coming right towards me and are very close already. Time to switch back to red and go up a few feet. As more experienced divers probably know, the lionfish of course they did not come after me at all... I may have thought so, but was not quite sure in the moment... After further "experimentation" I found out that they just like to hunt (just above ground - at least if it's sand) in the light. They were nearby all along. The place was sort of full of them, but they did not care about the red light. They sure loved white. The Stingray did not care about the red light and sure hated white (or at least that close..).
Anyway, filming under red light ... not good - I tried - maybe just to recall an observation e.g.: my at the time to me spectacular night time octopus observations under red light were just bland red video that nobody should have to watch.
The white light is good for video or "seeing" (and probably as macro light ... haven't gotten there yet) or clearing the way with dual "truck lights on".
The red light is good as focus light for a flash cam and for "observing" and the combo is good for having less stuff and weight. When hovering behind a chunk of reef w/o light, suddenly switching on two red lights (separated from each other in about eye distance of "something large") to red as a unsuspecting fellow diver is practically upon you also makes for good observing... And even so those red lights are darn bright for what one thinks of as a night vision preserving red light, they still do preserve night vision considerably better than even a fairly weak white light.
My red / white lights (big blue black molly 3) have 3 white levels (I think) and one red level and they do not have the function to switch red off when detecting a flash (I think some focus lights do that. maybe there are times when the red focus light otherwise would not be truly drowned out by the flash yet.. but I think (but don't really know) it's more about not causing red backscatter in an area near the lens intentionally not illuminated for that reason by the flash...

 

[bvanant]

For video they are completely useless (you want color in your subjects I suspect) but they are occasionally useful as a focus light for stills but in my hands at least most fish seem to find the red just as bad as the white.

One significant advantage though is that in areas where there are lots of worms/bugs at night the red seems to attract them much less.
Bill