Alan,
While dimming your lights
would help a little, you still get back scatter directly into your eyes.
Since this light travels a shorter distance than what you are illuminating, it
over powers the light reflected from the object of interest. You will
find that the more light you have the more you will see (and find
J). When a lot of light and filming or video
recording you may then have an issue with hot spots. Light diffusers,
wide reflectors, or off-angle light pointing can resolve these issues.
Phil had a spot and a diffused LED under development while we visited this
past fall. If I remember correctly, both lights had variable output
capability. The multiple high power LEDs were housed in an oil-filled
housing with a soft transparent lens. With the oil-filled housing the
walls could be thin and still be operational at great
depth.
As a side note, previous while
an avid wreck diver, we noted that we found a lot more ?valuable mung? when we
had brighter lights. Also, if we video recorded what we were exploring,
later review of the tapes revealed many items of interest that were overlooked
during the dive. Again, the more light we had, the more area recorded by
the video cameras. 5 Watt lights underwater are candles, we were running
dual 50 Watt rated bulbs at a higher voltage than they were rated for so they
produced even more light (down side, they were more sensitive to shock and had
a shorter burn life). HID lights were not yet available for
divers. This was for a diver-held light so we could be closer to an
object than you could be in a sub. Remember that light power falls off
with the cube of distance.
R/Jay
From:
owner-personal_submersibles@psubs.org
[mailto:owner-personal_submersibles@psubs.org] On Behalf Of Alan
James
Sent: Sunday, February 14, 2010 7:53 PM
To:
personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST]
Lighting
I was just looking
at a downlight at Jaycar
It says this light
produces 300 lumens from 5 watts.
They sell different
angled reflectors to add to some of their lights.
Do you or anyone
know the prefered reflector angle (beam angle)
Car lights put out
round 1000 lumens so I'm wondering what
lumens the
50 watt LED's
you're waiting on produce.
Jay, you mentioned
directing lights at an angle from your centre of vision
in low visibility
conditions. Wouldn't just dimming the lights work the
same?