How much light is too much light?

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Re: How much light is too much light?

Postby ChuckyBob » Fri Jan 29, 2010 1:27 pm

First of 100w is not a measurement of light. It is a measurement of power consumption.
A 100w halogen can not be compared to a 100wHID nor can either be compared to 100w for of LED's. You cant even compare 100w of one type of LED to another type.
I am sure you would have noticed the difference between your 20watt light and the 21watt HID's over the weekend.
The best way to measure light output is lumen. Its not perfect as many manufactured fudge the numbers buts its the best we have.
Lumen = total light produced ( not usually stated as the total light projected)
The other rating is Lux. Or how intense the light is. A finely tuned 3 watt LED can have a much higher lux than 100 watt for of LED's set up as a flood light even though the 100watt will have a higher lumen.

Lets look at some common hi output lights.
21w HID= about 1350 lumen
10w HID = about 500 lumen
P7 & MC-E LED's =700-900 lumen @ about 12 watt
Nem's, BB's @ Sels can lights produces about 800-1000 lumen
Pauls is about 1200 lumen
Mine is about 1200 lumen
My latest build is upto 2000 lumen.

The other important consideration is how the light is projected.

If all the light is in a 5 degree spot it will be 4 times as intense as the same light in a 10 degree spot. And 16 times as intense vs that in a 20 degree spot.
So what type of beam is best?

Wide beams can cause lots of back scatter in low viz conditions but are great for clear night dives
Tight beams are excellent for signalling and looking into cracks and crevices.

To be honest I think 2000 lumen is plenty if not verging on over kill.
Im very happy with the output of my 1200 lumen light but then my 420 lumen back up light ( that I think you had a go of at the weekend) works really well for most dives too.
On another forum I partake on there is a guy who wants to build a 6000 lumen light for diving in low viz. IMHO he is making a huge mistake and will end up with a very expensive light that will be of little use.
I do have one light that produces 4000+ lumen ( capable of up to 6000) but its my macro camera light and most strobes will probably produce more out put even if its just for 100th of a second.
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Re: How much light is too much light?

Postby ChuckyBob » Fri Jan 29, 2010 1:59 pm

Pete wrote: a robust - seriously robust


I cant help but think this (at some level) is a reference to Nems light and the 2 issues he has had with it.

I guess there are pros and cons of buying a custom made light locally as opposed to a mass produced light from a big manufacture.

With custom made lights like I do some design weaknesses can take time to show.
For example Nem has had a problem with the wires breaking inside the cable. As it turns out this has now happened to 3 lights in the space of two weeks and yet the design has not changed at all in the 2 years I have been making them. But obviously there is room for improvement and I have now found a solution that should minimise this problem. It can not be eliminated altogether but then this applies to all can lights not just mine.
The other problem with Nems light also has a solution and I very much doubt he will have that problem again.

I guess the point I am trying to make is with any design there will be some problems but its not until these problems show them selves that solutions can be found unless we have the foresite to recognise the potential problems. A large manufacture may produce a dozen or so prototypes for testing before mass production. But then this is often reflected in the retail price and also the fact they do not use the latest generation parts ans always seem to be 2 step behind custom builds.

Anyway.... the most robust lights on the market as I see it are all LED based. HID is too fragile.
Totally sealed designs help eliminate problems with opening and closing the canister or light head but I am unaware of anyone who does this after the closure of Solus.
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Re: How much light is too much light?

Postby Andy » Fri Jan 29, 2010 2:00 pm

Pete wrote:Whats the benefit of 'scary laser beams' in the overhead environment versus a good standards light?


Most lights used in that environment have a beam that is focusable down to around 6 degrees. The primary advantage of a tight beam is that your light is your primary signalling mechanism.waving your hand around with a floodlight is indistinct, whereas a narrow beam is really obvious plus you can tell roughly where your troubled team mate is.

As an aside, I personally find that a narrower beam really focusses your attention , irrespective of whether you are in an overhead or just night diving.

Using Greg's units, I am quite happy with a light that puts out around about 700 lumens - though in reality it is the lux that interests me the most. 700 lumens in a 14 degree angle is not the same as 700 lumens in a 6 degree angle.

During daytime diving, not in an overhead - 700 lumens is not enough to act as a signalling device. You want to be up there in 1000+ range for that - typically a 21W HID light.

To be honest, the amount of light isn't really that crucial a decision factor. My gut feeling is that if you decide what sort of burn time you are after, how robust you want the light to be, how reliable, what features (e.g. focusable/non-focusable)... then you'll probably end up with a very limited range of possible lights, at which point you can look at the light output and decide between them.
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Re: How much light is too much light?

Postby ChuckyBob » Fri Jan 29, 2010 2:19 pm

Pete wrote:
ChuckyBob wrote:A 100w halogen can not be compared to a 100wHID

Yeah, good point, should have said 100wHID and I don't know how many lumens... but certainly signficantly brighter than anything I have seen for underwater use.

Yeah, I find softer light is better in low viz... a bit like low beam in fog...

How have you found the 1200-2000 lumens in wrecks and caves?


Not sure I have seen or hear of a 100w HID system although some manufactures call their lights 100w HID when they are only 21w HID but "comparable" to 100w halogen.
My 2000 lumen light is yet to be finished but its not a huge difference to the 1200 lumen one which I find great in caves and wrecks and every where else. But then I do very little night diving.
I wouldnt say a soft light is good in low viz. More of a very tight beam with very little spill.
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Re: How much light is too much light?

Postby Andy » Fri Jan 29, 2010 2:37 pm

Pete wrote:Yes, the other factors, such as reliability and burn time are essential. I was more thinking about how lights have gotten so bright lately that you could almost think you were day diving! Then why not just dive in the day? And I did wonder if others had a similar thought about lights being so bright it no longer feels light a night dive.


I don't do much night diving, so it's not something I've really thought about in that context.

The amount of light is sometimes a non-issue, I'm sure that Jamie did a couple of the dives on your cavern course with no light at all; just in the same way that my lights are often off when teaching advanced wreck. Ambient light from other people's lights is more than you need.... I would want a brighter light for signalling during the day, but for dark environments my 10W light is fine.

I also think of it in terms of backup lights, I wouldn't want to have to go from a uber-bright monster light to a piddly light when the cacky has hit the fan. My backup lights are 1W LED, the drop down from a 10W to a 1W is not as much as 21W to 1W.... it would mess with my head a lot less...
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Re: How much light is too much light?

Postby Jason » Fri Jan 29, 2010 7:28 pm

Pete wrote:I was more thinking about how lights have gotten so bright lately that you could almost think you were day diving! Then why not just dive in the day?


Agree totally there as on many Night Dives, if I can get away with it, I just turn my light off and enjoy the experience from everyone else's outputs. Nothing like a cheap fright when someone in the group doesn't see ya coming. :) But thats what Night Diving is all about, 'Light' is there for the added effect - not to overide the experience totally.
The Groyne at Kiama has large Street Lights that spill over into the water so for some distance you don't really need a torch but you just fin around in a nice sombre ambient glow from above. This made a Buddy and I wonder about getting one of those Baby Walkers on wheels (the Dalek), attaching ample flotation and slinging one of those $60 giant torches (too hot to standing in front of real close and burn time of a few hours) in it pointing downward. Attaching it to a line and dragging it above us. We couldn't find a walker (think they are banned these days?) to be the sling frame. Shame really as I was hoping for some good photos with different colour filters from above.

I think both type of beams are useful and if there was a Torch that had both at the same time - 8)
I like the long narrow tight beam (the Light Sabre) as it helps judge distance provided by great penetration and is most useful for communication-location-attention of other divers.
I like the wide beam that is short in distance (the Ort Cloud) that gives the impression that one is moving in a faint bubble of light that is not too blaring on the eyes of oneself, other Divers and other critters but is enough to allow you to see (if you need to get something from your vest etc) without having to aim the torch constantly.

Does anyone know what effect 'Laser' lights have underwater? Do they penetrate much further, even in low viz conditions?
Just drifting along with whatever is current.
Currently I'm reading : The Art of Innovation by Tom Kelley.
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Re: How much light is too much light?

Postby NEMES1S » Fri Jan 29, 2010 7:38 pm

I am in full agreement on the light issues,and at the end of the day its not power its reliability.
Knowing that your primary light is reliable and charged and working is a great weapon in the mind game like battle that goes on when in a wreck or a cave or cavern.

I also do enjoy turning off my light during night dives,but I must admit I am in two frames of mind on doing so.
For one reason if you are diving with a group and they aren't expecting you to do so,it can become a "lost buddy" palaver in no time.
Also from a safety point of view,if something was to actually "happen"* to the "light-less" diver they have literally had it as fellow divers or even the coast guard will be unlikely to find you at night without a light source. (that said there are a lot that are willing to take that risk and I am one of them)

(*heart attack etc)
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Re: How much light is too much light?

Postby Jason » Fri Jan 29, 2010 9:17 pm

NEMES1S wrote:Knowing that your primary light is reliable and charged and working is a great weapon in the mind game like battle that goes on when in a wreck or a cave or cavern.

Totally agree with you there Nem. Especially when it comes to Wreck/Cave penetration and more serious Diving beyond a local 'fun' Dive, a reliable light source is more important than a 'type' of light source and I would definately not flick the switch so to speak. I only do things when it is safe to do so or there is an aspect of risk that can be compensated with without too much fuss.
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Re: How much light is too much light?

Postby NEMES1S » Fri Jan 29, 2010 9:43 pm

Vampire Squid wrote:
NEMES1S wrote:Knowing that your primary light is reliable and charged and working is a great weapon in the mind game like battle that goes on when in a wreck or a cave or cavern.

Totally agree with you there Nem. Especially when it comes to Wreck/Cave penetration and more serious Diving beyond a local 'fun' Dive, a reliable light source is more important than a 'type' of light source and I would definately not flick the switch so to speak. I only do things when it is safe to do so or there is an aspect of risk that can be compensated with without too much fuss.

Yeah,in a Wreck or a Cave I definately wouldnt be turning my primary off unless there was a VERY good reason.
On a night dive is the situations I was getting at,which I think you understood anyway....but just clarifying.. :D
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Re: How much light is too much light?

Postby Jason » Sat Jan 30, 2010 1:50 pm

Is there such a thing as a Xenon underwater light?
Australian Government is on the verge of making all Vehicles (currently the Holden Capri and Statesman) have Xenon lighting (an added $3,000) installed.
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Re: How much light is too much light?

Postby ChuckyBob » Sun Jan 31, 2010 5:34 pm

Xenon is a gas. It is often used inside some types of bulbs.

I think all HID's have xenon in them so my guess is that is what they are referring too.
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Re: How much light is too much light?

Postby Andy » Tue Jun 22, 2010 1:27 pm

"The brightest torch in the world".... or so they say.

http://www.wickedlasers.com/lasers/The_Torch-74-41.html


4100 lumens, pumps out so much heat that it will scramble eggs - so obviously not overly efficient, but bright ay? Not much use for diving, as it's got a burn time of five minutes.

I reckon Greg can do better. :wink:
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Re: How much light is too much light?

Postby ChuckyBob » Tue Jun 22, 2010 2:30 pm

At 4100 lumen it's a long way from the brightest torch. Still mighty impressive.
I have just finished a 1500 lumen dive light, already have a 5000 lumen+ camera light and am working on a 3600 lumen spot light for the coastguard. Originally it was going to be 6700 lumen but heat is too much of an issue.
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Re: How much light is too much light?

Postby Andy » Tue Jun 22, 2010 2:42 pm

ChuckyBob wrote:I have just finished a 1500 lumen dive light, already have a 5000 lumen+ camera light and am working on a 3600 lumen spot light for the coastguard. Originally it was going to be 6700 lumen but heat is too much of an issue.


You should contact the Guiness records people, as they are investigating the "world's brightest torch"..... I guess they are wriggling around some definition of "torch".
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Re: How much light is too much light?

Postby ChuckyBob » Tue Jun 22, 2010 5:13 pm

I guess you could define torch as a single piece self powered, hand held light source.
None of my above project fall into that category.
But here is a light that does and puts out a claimed 9000 lumen. Judging by the components used it probably does or at least beats 4100 lumen.
http://www.youtube.com/watch?v=vlzFg15L ... re=related
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