HiD Vs LED - Where are we today?

[AMW]

Having worked in sumps with both HID and LED in poor vis the punch power of a HID is far better than a LED. I have recently replaced my umbilical HID with another. Of course the down side is the (possible) fragility of the light unit (not cheap) although in five years I have only damaged one. Also at present the weak dollar gave me the ability of buying a Dive Rite HID (Dive Rite express) It took three days to arrive and still a good price ,even with import duty.

I run my HID helmet mounted with three back up LED,s (Tektite EXPEDITION STAR,s)



This is Colin`s with a FAMi (LED) do not have a HID picture to hand

Andrew.

[Rob Dobson]

Originally Posted by KiwiMagic

I've read the articles here, and have to confess - I really just want someone to say - "this is the best torch for the price you want to pay". At the end of the day, cost is a factor £300-£400 but (even though for some this might be the minimum £'s for a torch) it still seems a heck of a lot of money to pay for a torch. I also want it to have a reasonable burn time (lets face it, assuming 2 dives a day, I would need at least a 90 minute burn time)

Can someone suggest from experience the best HID and the best LED for that price range. Is an umbilical out of the question for this price range? Second hand I would happily go with.

In that price range I'd look at a 2nd hand 10W 4.5ah or 9ah Salvo from when people take the step up to 21W or 35W. They normally go for £150-£300 and if you want to make the beam even tighter you can get an EKPP reflector head.

There was a 21W 5.6ah Li-ion that was sold round these parts a few weeks ago for around £400 and that was practically a new light (utter bargain). So they do come up if you're patient.

[KiwiMagic]

Thanks Rob

Appreciate the feed back. I will keep my eyes and ears open

Dave

[Salvo]

Originally Posted by Martin Owen

Barry,

Don't you think a better comparison would of been to have the camera fixed on a tripod, with the focus set manually, then turn one light on & photo it, turn off, then turn another on & so on.
The conditions would then be identical & it would be just the lights you were comparing.

B.S. claims (by whoever) are just misleading and only the only person they fool in the end is the one making the false claim.

There IS a huge difference between HID & LED, but the biggest seems to be whether you want either a spot light on a very tight area (for signaling etc) or a good wide usable beam, i for one would be really interested in seeing photo's of HID's in a wide beam to see a true comparison, as i would hazard a guess that this is where Solus are making there claims?? (it would be foolish otherwise as an LED cant as yet be focused tightly to give a small but bright spot)

So HID's are great at a very bright narrow beam, ideal if you need it for signaling and LED's are great at a 'normal use' wide spread light, with bulbs that are almost indestructible.

The biggest single factor when i bought my light was that it must be as indestructible as possible, which left only an LED light.

Martin,
Take a look at the pictures again. I did open the 35 watt HID beam up to match the SU-1250. Look at the lumen output I had written below each light. The 2000 lumen output of the 35 HID was over 10 times the 180 lumen output of the SU-1250. Now if you remember my whole issue here has been the false claim the 1250 was comparable to a 35 HID. Adding 6 LED emitters to get a total of 1250 lumens ain't no 3000 lumen of a 35 HID. The light meter really told the whole story. Adding 6 emitters together is very inefficient in terms of output. A single light source is a far more efficient light source. Another advantage of a single light source is the ability to focus the light from a wide to a spot. There is nothing wrong with LED lights. We believe they make the best backup light. They can also make a good primary light. I see absolutely no reason to make false claims about either light source.

Barry

[divingniknaks]

Originally Posted by KiwiMagic

Thanks Rob

Appreciate the feed back. I will keep my eyes and ears open

Dave

Or you could consider this 10W HID Hand held light, 10 watt Hand Held light at divingniknaks 0121 707 5783. Frog, Dirzone, Agir Brokk Scuba Diving Gear

Would fit your requirements as per your earlier post.

HTH

.

[Rob Dobson]

Dave if you went with this one I'd get the optional Goodman handle as well.

[divingniknaks]

He already got it


.

[KevinJ]

I have read with interest some of the fascinating posts on YD and thedecostop from Barry Miller (Salvo Diving) and Rob Dobson. For the most part I’ve tried to stay clear and hope that most divers are smart enough to see Barry’s posturing for what it is; A means to protect his business.

Of particular interest are the posts and photographs cross-posted on both forums to disprove the “false and misleading claims made by SOLUS as to the output of their product” as Barry puts it.

As a number of people on YD have pointed out, the test is hardly being conducted by the most impartial person. Some have also pointed out flaws in this “testing”.

The obvious flaws are:

• The test is being run in air and not in water. The SOLUS SU-1250 will lose 1% of it’s light output for every degree C over the design temperature. If left running for more than a minute the light output will have dropped by up to 25% from it’s design rating.
  Conversely the HID lamp will produce slightly more light in air when it runs hotter.
• The test is being run in air and not in water. The beam angle of the light will narrow by almost 1/3rd when placed in water, due to the same refraction that causes things to look larger and closer when you’re underwater. As the beam angle becomes narrower and the illuminated area smaller, the light intensity increases. The wet reflector design used by Barry Miller in the Salvo lights maintains the same beam angle in/out of water.
• You cannot characterise a beam by taking one measurement with a light meter.
  The correct method is to take multiple measurements at various positions within the beam and average these to get a number, which will represent the amount of light present.
• Barry repeatedly misrepresents the measurements as Lumens. The measurement you get from a light meter is Lux, not Lumens. The definitions are referenced at the bottom of this post, for those who want to know the difference.

Of particular interest was the photograph showing the 10 Watt focusable Light Vs SOLUS SU-1250. Assuming that this photo was taken with the SU-1250 on full power, this image should be a good starting point.



We took this image and ran an analysis on it using E-Vision Capture, a piece of software designed and used by professionals in the machine vision and lighting industry for image analysis. This is the original image – there has been no post-processing of any kind.

Barry Miller claims that the SOLUS produces less than a quarter of the light of a 10 Watt HID lamp. A measly 180 Lumens as opposed to the mighty 800 Lumens from the HID. What Barry is actually measuring is Lux. There is a relationship between Lux and Lumens but they’re not interchangeable.

Below is the 3D surface profile of the image showing the relative light output from the (left) 10Watt HID and (right) SU-1250. The volume under the mounds represents the total luminous output of each of the beams.
The Z axis or height is generated from the illuminance of the image. (The contrast of white to black)



From this perspective it’s obvious that the 10 Watt HID has a higher intensity at the centre of the beam, however it’s not by much (between 10% and 15%). For some strange reason this doesn’t seem to match up with the numbers quoted by Barry. You’ll also note that the mound on the right (SU-1250) while having a slightly lower intensity, covers a much greater area. (this is important)

The next image shows a plot of the illuminance over the original image.



The area under the red plot line represents the amount of light in the image passing from left to right (Sum of the light in the y axis).
As you can see, the area under the plot line for the HID is approximately 1/3rd of the area under the plot line for the SU-1250.
It is clear from the plot that the SU-1250 produces at least 3 times the amount of light of the Salvo 10 Watt HID.

This would support our claims that the SU-1250 produces the same amount of light as a 35 Watt HID lamp. Given that the SU-1250 being tested was being run in air it would likely have been running 20-25% under it’s rated light output anyway. (If it was even set on full power)

I have no doubt that Barry will come back with claims that it’s all smoke and snake oil but it isn’t. It’s just a little bit of science and mathematics.

We encourage anyone who is suitably qualified and has access to tools such as MatLab or any of the other excellent image analysis packages to validate this with the images posted by Barry.

As far as Barry Millers statement regarding “false and misleading claims” made by SOLUS, how does he justify his claims that the Salvo 10 Watt HID lamp tested produces 800 Lumens and the SOLUS SU-1250 produces 180 Lumens?

I had hoped that this wouldn’t come to a debate on a public forum but Barry Miller’s (and Rob Dobson’s) repeated attacks didn’t leave too many options.
I would hope that this will put an end to the argument and has sufficiently demonstrated that the SOLUS SU-1250 produces at least 3 times the light output of the 10Watt HID lamp used by Salvo. And that this has been demonstrated using the images supplied by Salvo.

I generally try not to debate physics, as physics is what it is. It doesn’t change no matter how much you argue over it.
In particular I try not to debate with a fool as sometimes it’s hard for onlookers to tell the difference

For those who want to make up their minds for themselves, visit our stand at the DIVE2007 show in October, We’ll be on stand 1154 in Hall 9. For those further away, one of us will be on the Oxycheq stand at DEMA to answer your questions.
We’ll have all our products on display and our demonstration box there to show how a 10Watt HID, 35 Watt Halogen and a 250 Lumen LED Array (1st generation) all produce similar light levels with the same beam characteristics. If anyone isn’t clear on the refraction of the light beam in water we can even bring a fish tank along to demonstrate this effect.

Kevin Jury,
Managing Director
Solus Submersible Products


LUMEN:
A unit of light flow or luminous flux. The lumen rating of a lamp is a measure of the total light output of the lamp. The most common measurement of light output
(or luminous flux) is the lumen

LUX: The metric unit of measure for illuminance of a surface. One lux is equal to one lumen per square meter.

[Garf]

What it boils down to, and do feel free to correct the technical aspect of my statement, is that if you want a tighly focussed beam with a hot centre for looking into small holes, or for signalling and general communication then buy yourself a Salvo. The DIR mob use them for this purpose. If you want bolox loads of light spread over wider area for more general illumination then buy yourself a Solus. everything else is marketing-speak.

You're never going to get a torch good for everything, so why don't you guys both play nicely and play to the strengths of your respect products rather than cat fighting. You both sell superb torches, they just do different jobs.

[KevinJ]

Originally Posted by Garf

You're never going to get a torch good for everything, so why don't you guys both play nicely and play to the strengths of your respect products rather than cat fighting. You both sell superb torches, they just do different jobs.

Good point. The cat fighting was what we were trying to avoid. It was just getting hard to ignore the nonsense.

Regards,

Kevin