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--------------08C00FB73B0E0D69329AA13C Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Here is a quality post on HID lights from Dan Mackay in a response on the Techdiver.com discussion group Hi Max, The HID works great. It is a marvellous piece of kit. It is kind of funny the way I use it though. I thought that it was an all purpose light and I guess in general it is. I find however that it shines (pun intended) in pitch black clear water. In moderately silty water it is a great performer as well. In really silty water I take the HID off and put the 50 watt halogen back on. I use the 14 watt HID and it far outshines the 50 watt halogen. I have not done a side by side comparison but I would say that it is every bit as bright as the 100watt halogen (24v) system that I have used for video. The problem that arises in water that is not completely dark is that the HID is 'too' good. It burns at a color temperature of ~5500kelvin. It is practically invisible except for the object that you are illuminating. For example imagine this. Turn on a normal incandescent light in the water and you will see the path that the light is taking by the yellow color and also the object that you are trying to illuminate. There are a couple of factors at work here like refraction and diffusion. Turn a HID on in the same clear water and if you are not shining the light on something you cannot tell that it is even turned on except when you look into the lens! This makes for a great light for the cold dark wrecks and as long as it is dark it works excellent in silty water. It is the mid water, not quite dark were the characteristics that make these lights so wonderful work against them. Other than being able to see for miles with these lights, Halcyon has made some modifications to the light head. I think I got one of the used one the the first of the new style that Barry Miller made. The new ballast is flat and sits nicely down on behind your wrist. It is far better in terms of comfort than the old box style. If you buy a light make sure you get one with an EO connector and send your existing light head down to have an EO connector put on. (That is if you have a test tube style light head). That way if the HID dies it is a simple matter of changing light heads in water. I always carry a spare test tube light head. I had a HID die as I was at the bottom of the tube going in the upstream side of Cow. For those folks that know this cave and that particular spot know how tight it is. It took me about 30 seconds to swap heads and continue the dive. It is like carrying two primaries! Another consideration is the burn time. I get better than three hours burn with the 14 watt HID. I only need to charge it once a weekend. Big consideration for remote areas. As for the 18 watt, my buddy Johnny has one and I can't tell the difference. It is sort of asking how bright is bright. That is a 22% increase in the wattage but once again it looked the same to me. The 40 watt version should really be kick butt. I would think that its real application would be for high end video. Once you purchase a light you are stuck with that particular ballast. The differnt watt bulbs are not interchangeable. The are a heck of a light and if you have enough money I would recommend them to anyone. Be prepared for the sticker shock. Dan --------------08C00FB73B0E0D69329AA13C Content-Type: text/html; charset=us-ascii Content-Transfer-Encoding: 7bit <!doctype html public "-//w3c//dtd html 4.0 transitional//en"> <html> <i>Here is a quality post on HID lights from Dan Mackay in a response on the Techdiver.com discussion group</i> <p>Hi Max,<i></i> <p>The HID works great. It is a marvellous piece of kit. It is kind of funny <br>the way I use it though. I thought that it was an all purpose light and I <br>guess in general it is. I find however that it shines (pun intended) in <br>pitch black clear water. In moderately silty water it is a great performer <br>as well. In really silty water I take the HID off and put the 50 watt <br>halogen back on. <p>I use the 14 watt HID and it far outshines the 50 watt halogen. I have not <br>done a side by side comparison but I would say that it is every bit as <br>bright as the 100watt halogen (24v) system that I have used for video. The <br>problem that arises in water that is not completely dark is that the HID is <br>'too' good. It burns at a color temperature of ~5500kelvin. It is <br>practically invisible except for the object that you are illuminating. For <br>example imagine this. Turn on a normal incandescent light in the water and <br>you will see the path that the light is taking by the yellow color and also <br>the object that you are trying to illuminate. There are a couple of factors <br>at work here like refraction and diffusion. Turn a HID on in the same clear <br>water and if you are not shining the light on something you cannot tell that <br>it is even turned on except when you look into the lens! This makes for a <br>great light for the cold dark wrecks and as long as it is dark it works <br>excellent in silty water. It is the mid water, not quite dark were the <br>characteristics that make these lights so wonderful work against them. <p>Other than being able to see for miles with these lights, Halcyon has made <br>some modifications to the light head. I think I got one of the used one the <br>the first of the new style that Barry Miller made. The new ballast is flat <br>and sits nicely down on behind your wrist. It is far better in terms of <br>comfort than the old box style. <p>If you buy a light make sure you get one with an EO connector and send your <br>existing light head down to have an EO connector put on. (That is if you <br>have a test tube style light head). That way if the HID dies it is a simple <br>matter of changing light heads in water. I always carry a spare test tube <br>light head. I had a HID die as I was at the bottom of the tube going in the <br>upstream side of Cow. For those folks that know this cave and that <br>particular spot know how tight it is. It took me about 30 seconds to swap <br>heads and continue the dive. It is like carrying two primaries! <p>Another consideration is the burn time. I get better than three hours burn <br>with the 14 watt HID. I only need to charge it once a weekend. Big <br>consideration for remote areas. <p>As for the 18 watt, my buddy Johnny has one and I can't tell the difference. <br>It is sort of asking how bright is bright. That is a 22% increase in the <br>wattage but once again it looked the same to me. The 40 watt version should <br>really be kick butt. I would think that its real application would be for <br>high end video. <p>Once you purchase a light you are stuck with that particular ballast. The <br>differnt watt bulbs are not interchangeable. The are a heck of a light and <br>if you have enough money I would recommend them to anyone. Be prepared for <br>the sticker shock. <p>Dan <br> <br> </html> --------------08C00FB73B0E0D69329AA13C-- -- Send mail for the `techdiver' mailing list to `techdiver@aquanaut.com'. Send subscribe/unsubscribe requests to `techdiver-request@aquanaut.com'.
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