Designing a focusable LED dive light.

350xfire

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I like it... Wonder if it will work with P7, SST by modifying. I don't really care to have it adjustable for my lights, but this way I acould have one reflector do it all. I would just determine what I want set it for that and glue it together so it won't move. ANyone stocking it? How much?... I have not been able to find it yet.
 

350xfire

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Thanks 350. But I believe aspherics are the way to go.

Pack, have you found any aspherics that are MR-11 sized (40MM) that can take the beam of a larger LED (P7, SST) without making it look square, irregular or just not nice and round? That's the only thinkg I have against aspherics...

BTW, I do like the SST-90 aspheric you have built when the beam is round.
 

lucca brassi

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350Xfire....

You can made cover over led with round hole on the top if you prefer round projected shapes. Problem it is not in emiter but in form of LED.

Round projected contour from squared emiter it is basicly deformation of ray out of lens focus .
 

350xfire

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350Xfire....

You can made cover over led with round hole on the top if you prefer round projected shapes. Problem it is not in emiter but in form of LED.

Round projected contour from squared emiter it is basicly deformation of ray out of lens focus .

Good point. Had not thought about that
 

Packhorse

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I have not really looked at a MR11 sized aspheric yet (35mm isnt is?).
But I think MG will make one that will fit.

Whats wrong with a square beam anyway? If you really want round just defocus it but that does mean a larger spot.
 

Codiak

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Are we over-thinking this issue?
I started playing with something modeled on hanachan's design and had one of those aha moments.
I decided to use my fish tank for testing ( I need to clean it soon)
At 1.5meters wide its a reasonable test chamber.

As previous tests, per hanachan's thread, I used the macro lense mounted in front of my Tusa dive
light, making a nice wide light and nice tight spot.
After putting the Lens, pvc tube and Tusa together I covered the lense with
seran wrap.
Baseline shot... from outside the tank
http://picasaweb.google.com/BeaverLakeNe/CPF#5430785801006454418

Next up from under water
http://picasaweb.google.com/BeaverLakeNe/CPF#5430785812135448114
Great no surprises, nice and tight
One of the posts from Packhorse mentioned the need to have an air damn between the aspheric lense
and contact with the water to maintain a tight beam which is why I had the seran wrap on the front side of lense.
To demostate the value of this air damn I removed the seran wrap.
http://picasaweb.google.com/BeaverLakeNe/CPF#5430785824055049090
Confirmed.
Of course it's important to see the wide angle baseline of the Tusa light without another lense
http://picasaweb.google.com/BeaverLakeNe/CPF#5430785833687619170
okay, so no surprises...

Except............

For these tests I never sealed the Tusa within the PVC... the tube was flooded.

Turns out an air damn is not required between the LED and Lense!
Using the PVC as a sliding sleeve yields variable focus
ttp://picasaweb.google.com/BeaverLakeNe/CPF#5430797673013350946
Obligatory video
http://www.youtube.com/watch?v=pECAsR1SAuM

Visably I don't notice a drop in the intensity of the spot regardless of flood but I'd be willing to trade a few lumens for the flexibility to focus!!!!

For these tests the Travel distance from wide to spot was less than 50mm....
I may even order a DX asperhic and retest this.



A Heatsink mounted LED moving within a PVC tube is
be an easy build if we don't have to worry about sealing the tube against water.

If the Tusa is any example any single bin divelight could be focused with a "cap"

Comments?
 

gcbryan

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Just thinking a bit out of the box here but since a focusable light is somewhat hard to accomplish wouldn't much the same thing be accomplished with a standard fixed focus tight spot light and a diffusion filter adapted to quickly snap over the front of the light?

Not as elegant either in having to snap it on and it wouldn't be variable...either spot or totally diffused but isn't a diffused light more or less the same as a wide angle beam?
 

Codiak

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Just thinking a bit out of the box here but since a focusable light is somewhat hard to accomplish wouldn't much the same thing be accomplished with a standard fixed focus tight spot light and a diffusion filter adapted to quickly snap over the front of the light?

Not as elegant either in having to snap it on and it wouldn't be variable...either spot or totally diffused but isn't a diffused light more or less the same as a wide angle beam?


for personal use it's an implementation of two extremes and is the solution I currently use... some of it maybe ***** envy when diving with my HID buddies... more if it is needs change during a dive and filters are inconvient and less effective. Remember filter = lower output.

for guys selling lights, it's hard to convience people or keep them happy if you take functionality away from them... want to convert HID believers you better have VF
 

Goldigger

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Where are you going to stash the snap on filter? If it was attached to the light then its not so much of a problem, but if its in a pocket trying to get it out and on with 5mm gloves could be a endless task.
 

gcbryan

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Where are you going to stash the snap on filter? If it was attached to the light then its not so much of a problem, but if its in a pocket trying to get it out and on with 5mm gloves could be a endless task.

This would be the least of the problems. I'm just throwing it out there that maybe this might be a work around in certain cases.

You could either do it like some camera housings do which is to have a slot in front of the lens for the filter, tie a short string to the filter so it's always with the light.

You could also just have two backup lights and install the filter on one of them (removable).

I have a filter than came with a Light Cannon and have tried it out above water but have never bothered to try it out underwater. I'll try it out one of these days.

I think I like the idea (if at all) of putting it in the backup rather than having it attached by a string and floating around when not in use.

If you were moding a light you could attach a filter in front of the lens as a swing away much like the filters on a darkroom enlarger. The filter sticks up until needed and then you simply rotate it to the down position.

That would be easier/cheaper/simpler than creating the focusing mechanism for a variable focus light.
 
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Goldigger

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This would be the least of the problems. I'm just throwing it out there that maybe this might be a work around in certain cases.

You could either do it like some camera housings do which is to have a slot in front of the lens for the filter, tie a short string to the filter so it's always with the light.

You could also just have two backup lights and install the filter on one of them (removable).

I have a filter than came with a Light Cannon and have tried it out above water but have never bothered to try it out underwater. I'll try it out one of these days.

I think I like the idea (if at all) of putting it in the backup rather than having it attached by a string and floating around when not in use.

If you were moding a light you could attach a filter in front of the lens as a swing away much like the filters on a darkroom enlarger. The filter sticks up until needed and then you simply rotate it to the down position.

That would be easier/cheaper/simpler than creating the focusing mechanism for a variable focus light.

If you've got two backup lights just take one that has a spot beam and the other with a floodier beam.
Save your self the hassle of messing about with clip on diffusers... Not really seeing the point in doing it to backup lights anway.
 
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