• Welcome to ScubaBoard

  1. Welcome to ScubaBoard, the world's largest scuba diving community. Registration is not required to read the forums, but we encourage you to join. Joining has its benefits and enables you to participate in the discussions.

    Benefits of registering include

    • Ability to post and comment on topics and discussions.
    • A Free photo gallery to share your dive photos with the world.
    • You can make this box go away

    Joining is quick and easy. Login or Register now by clicking on the button

LED vs HID

Discussion in 'Cave Diving' started by RescueTechDiver, Jul 27, 2007.

  1. D_B

    D_B Kimber/TekDiveGirl storyteller and memory keeper ScubaBoard Sponsor

    # of Dives: 50 - 99
    Location: San Diego, Ca.
    14,662
    6,993
    113
    Good review, good info, good answers to questions, thanks Kevin
     
  2. PerroneFord

    PerroneFord DIR Practitioner

    # of Dives:
    Location: The Borg Cube
    6,018
    33
    0
    I don't see why that would make anyone mad. It reinforces exactly what we've said here. The Solus seems to be a very good light, but as yet, lacks the punch and reach of the HID for signaling purposes and distance the light carries.

    I did note that they used a Salvo that was several years old. I haven't seen a clear top Salvo can in quite a while. Nor have I seen one with the large square ballast head. They've moved on two generations since then. I wonder how the test would have fared with a modern Salvo against the modern Solus.

    -P


     
  3. ArcticDiver

    ArcticDiver Solo Diver

    1,831
    5
    0
    I suggest that analysis by people with economic interests be viewed cautiously. On the other hand people do get emotionally connected to whatever their choice is which makes their comments subject to some scrutiny. What to do to get "facts"?

    In most communities, with the tens of thousands of dollars of lights around a person can generally find one of each kind of technology. Take them for a test drive. See for yourself in your own circumstances.

    One dealer let me do that. First I compared the lights in a clear, dark warehouse. Then I was able to compare them in a large building with some smoke in it. Finally I took both lights diving in both clear Carribbean style water and the obscured water common in the Pacific Northwest and some of the ponds I "get" to dive in.

    The results for me were that the LED lights were wonderful in clear water, or air. Combined with their long battery life and resistance to shock they obviously were the light of choice.

    On the other hand, if there was any obscuration like smoke, particulates in the water, or anything else the HID lights were without any shadow of doubt the best. They peneterated better. They gave better visibility.

    Even Xenon lights were better than any LED light when it came to actually seeing something in the real world condition. LEDs were a distant third. They were almost always "brighter" but the light didn't penetrate to allow the user to see as well as the HID or Xenon.

    It is your money. Do your own test and see how each light technology performs in your environment. Bet you will agree that, all things considered, in clear water LED is probably preferable. But, in anything less than clear HID, or even Xenon, is more useful and therefore preferrable.
     
  4. D_B

    D_B Kimber/TekDiveGirl storyteller and memory keeper ScubaBoard Sponsor

    # of Dives: 50 - 99
    Location: San Diego, Ca.
    14,662
    6,993
    113
    Comparable lights to the ones discussed here?
    .. I admit to being a light novice, and I may be wrong here, but I was thinking that a 10w, 20w, 30w, HID lights from one manufacturer are pretty much comparable to another 10w, 20w, 30w HIDs .. but that is not the case with LED lights, one LED manufacturer not being the same as other LED light manufacturer .. maybe it would be if you kept the same criteria, IE: LED watts from one manufacturer to LED watts from another
     
  5. ArcticDiver

    ArcticDiver Solo Diver

    1,831
    5
    0
    Yes, but you miss my main point. Don't blindly trust comments made by people who have economic or emotional interests in the products. Verify how the product fits YOUR diving. Take the lights for a test dive in the environment you
    dive in.

    Don't over think the problem. You can either see what you want to in the enviroment you use the light in, or you can't. My testing says that if it is an obscuration filled environment the HID does a better job of penetrating to the objects I want to see than the LED. Someone called it The Light Sabre Effect. While not very analytical that is a good term to describe what I'm talking about.

    So, give the keyboard a rest; get a couple lights and go test.
     
  6. 300bar

    300bar ScubaBoard Supporter ScubaBoard Supporter

    # of Dives: 5,000 - ∞
    Location:
    7,433
    105
    63
    I fail to see your point on the economics :confused:
    As for compairing LED vs HID you are right on.

    Clear water= LED
    Murky water= HID
     
  7. PerroneFord

    PerroneFord DIR Practitioner

    # of Dives:
    Location: The Borg Cube
    6,018
    33
    0
    You'd like to think so, but unfortunately, it's simply not the case. What bulb is being used has a bearing on light quality, but more importantly, the reflector has a major bearing on both the amount of light being cast forward, and it's quality. A quality reflector will concentrate the beam and produce a nice pattern. A poor quality reflector will not focus as much light going forward. Think of it like a satellite dish. Do you think you will do capture a better signal with a cheap, 2ft dish, or a quality 8ft dish? Size matters as does shape.
     
  8. KevJ

    KevJ Angel Fish

    9
    0
    0
    Hi, just a couple of points.

    1. RegardingEconomic interest.
    Mark Chase, the guy who did the SU-1250 review, is not connected to SSP in any way.
    I contacted him about doing the test because he has done a number of equipment reviews over the years and tends to put a lot of effort into it.
    He's not writing for a magazine or any specific website and does these reviews off his own back to help other divers. He's also fairly well respected within the UK tech / rebreather diving community and has a reputation for calling a spade a spade.
    I doubt there was any emotional attachment involved as he's been diving with the Salvo for years. (Next point...)

    2. Mark does state in the review that the Salvo is a 2004 model. He also points out that he's upgraded it to the new bulb. I don't think he intended the side-by-side tests to do anything but give people a direct comparison of the SU-1250 against what many consider to be the standard for technical diving.

    Edit
    3. All lights are not created equal.
    Making any type of comparison or evaluation of a diving light based purely on specification is very difficult.
    HID lamp output can vary depending on the manufacturer of the bulb, the type of reflector used, the design of ballast. Within manufacturing there can be variance between two bulbs from the same production line.
    LED based lights are also subject to this rule. LED die vary in efficacy from 20 lumens per Watt (lm/W) to over 100 lm/W. Some designs use efficient optics to shape the beam and some dont.
    The lumen figures quoted by some manufacturers may only be the source output and not take into account the efficiency of the optics (reflector/lens).
    Watts doesn't really indicate any more than how much power the leds burn. It has no bearing on light output.
    I have seen 3 Watt LED die emit twice as much light as a 5 Watt LED.
    Sometimes Watts is used to give a comparison against another light source. Even this has it's issues. Was it compared against a good quality halogen bulb or a cheaper brand.

    Whether the light is in air or water can even have an effect on the perceived performance. Most lights will benefit from the refraction of light as it passes out of the light into the water. This causes the beam to narrow by almost 1/3rd. As the beam narrows the area illuminated becomes smaller and the intensity of the light increases - by as much as 2.25 times (depending on water salinity, temperature...)
    Designs using wet reflectors (Salvo, Halcyon, Diverite) don't benefit from the effects of refraction in the water as the beam shaping is done once the light has already passed into the water. In this case the beam angle above water is exactly the same as below water.

    Theres more information on this here SOLUS Submersible Products.

    Regards,

    Kevin
     
  9. D_B

    D_B Kimber/TekDiveGirl storyteller and memory keeper ScubaBoard Sponsor

    # of Dives: 50 - 99
    Location: San Diego, Ca.
    14,662
    6,993
    113
    Thanks ArcticDiver, and I understand
    ... trying out the lights first, good advice and I wish I could, and I'm not likely to have the funds to purchase a can light anytime soon, but I'm still interested in the subject

    Thanks Perrone, as an off roader, I do understand about the importance of reflectors in light output .. just forgot, it must be those lemming brain cells .. they're all jumping off the cliff :wink:
     
  10. kuster500

    kuster500 Instructor, Scuba

    # of Dives: 200 - 499
    Location: Columbus, MS
    46
    0
    0
    I tried out the Solus 2500 at JB, and I liked it so much I bought one...everyones different though
     

Share This Page