Buadhai
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I do not. I'd be glad to try and figure it out, though. Any ideas?
(Gear is packed up now for a trip to Koh Chang. Back at the end of this week.)
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I do not. I'd be glad to try and figure it out, though. Any ideas?
(Gear is packed up now for a trip to Koh Chang. Back at the end of this week.)
HenrikBP
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Really nice idea. Neat how the designer used pipe and similar material pipe inserts to hold the lenses in place.
Henrik
Henrik
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I believe that was designed by H. Wes Pratt (prototype for "Winch" in the book and movie "Jaws"), now of Motte Marine Lab, you can find him on Facebook, really nice guy.
Charlie99
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Stick something in through the hole in the side an wiggle it around while facing the unit towards the sun to see more or less where to sun image comes to a point ?
If it doesn't disassemble easily, then it would be difficult to measure anything. Obviously it has served you well for 15 years and you shouldn't tinker with it and break it.
I'm headed back to the mainland in another week, and can scrounge up some lenses to try out the technique.
Buadhai
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I'll give it a shot. There is a big hole to let water in which might allow me to get a decent guess at the focal pint.
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If you just take the trouble to send Wes a note he will, I am sure. be glad to tell you the focal lengths and even where to get them.
Charlie99
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But then I wouldn't get the enjoyment of re-inventing the wheel.
Buadhai
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Finally back home after a hellish trip to Koh Chang. Diving fine. Bus to Koh Chang a nightmare.
Back on topic: I'm not sure if this makes any sense, but the focal length of the two lenses seems to be the same as the distance between the two lenses. I turned the thing toward the sun and put a length paper in one of the fill holes and moved it back and forth. The sun's image was smallest when the paper was touching the inside surface of the back lens.
Also, if you just look through one of the lenses, it seems to be focused exactly on the surface of the other lens.
I hope that helps.
Back on topic: I'm not sure if this makes any sense, but the focal length of the two lenses seems to be the same as the distance between the two lenses. I turned the thing toward the sun and put a length paper in one of the fill holes and moved it back and forth. The sun's image was smallest when the paper was touching the inside surface of the back lens.
Also, if you just look through one of the lenses, it seems to be focused exactly on the surface of the other lens.
I hope that helps.
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