True Focusable Light?

[gcbryan]

Not that I want one but I'm curious as to whether anyone out there produces a true focusable light?

Meaning that rather than having the light focused at the spot setting and then just throwing it out of focus for flood it is focused at spot and at flood?

So in other words it's efficient lumen-wise all the time.

This would be the same concept as a photographic zoom lens.

 

[Packhorse]

Not that I know of. Nor can I think of any benifit. Then only true focused lights are aspherics. Every thing else like TIR and reflectors are all out of focus.

 

[Packhorse]

It wouldn't have a constant lumen output either just like a cameras zoom lens can't hold a constant f stop.

 

[gcbryan]

It would have greater lumen output in theory though wouldn't it by having the flood be at the focal point as well?

I realize that multiple lens would be involved to be able to do this and now that I think about it the multiple lens would reduce the lens efficiency.

I guess the quality of the beam would be improved...maybe?

 

[joema]

Not that I want one but I'm curious as to whether anyone out there produces a true focusable light?..

The Surefire UA2 Optimus was planned to be a true focusable light, but it was cancelled: http://www.brightguy.com/products/SureFire_UA2_Optimus.php#

 

[paulr]

Not that I want one but I'm curious as to whether anyone out there produces a true focusable light?

Meaning that rather than having the light focused at the spot setting and then just throwing it out of focus for flood it is focused at spot and at flood?

So in other words it's efficient lumen-wise all the time.

This would be the same concept as a photographic zoom lens.

Yeah there was one made for the movie industry, I'm trying to remember its name. It was a snooty sounding double name, like Pritchard-Mitford or something like that. It was pretty expensive but looked well made. The fancier version had a 3-element optic. I was sort of tempted to buy one. I don't think it's made any more. The typical adjustable-reflector light preserves that lumen efficiency, but doesn't exactly make a focused beam.

 

[Packhorse]

I guess the quality of the beam would be improved...maybe?

That would all depend on what you consider optimal.

For video I would like a very even rectangular beam in a 16x 9 ratio
But next best is a round even beam. Exactly what an out of focus aspheric gives.

An in focus aspheric does not really give a perfect beam. Just a perfect projected image of the LED die.

 

[gcbryan]

That would all depend on what you consider optimal.

For video I would like a very even rectangular beam in a 16x 9 ratio
But next best is a round even beam. Exactly what an out of focus aspheric gives.

An in focus aspheric does not really give a perfect beam. Just a perfect projected image of the LED die.

By improved beam quality I was thinking of some of the artifacts (edge in particular) of some aspherics. I've only played around with some cheap aspherics so I don't know what the beam quality is like with better aspherics.

 

[Packhorse]

Well yes, aspherics need to be quite out of focus before the beam becomes very even. And even then there may be some colour shift near the edge but its no real problem unless looking at a nice white wall.

 

[Codiak]

Well yes, aspherics need to be quite out of focus before the beam becomes very even. And even then there may be some colour shift near the edge but its no real problem unless looking at a nice white wall.

Having just put my first SST-50 together... vah vah voom...

For video I'd serious thinking just raw LED the smooth wide angle is just fantastic


Earlier tests with focusing slider work perfectly now just need to water proof the thing

 

[Packhorse]

If you use it with no reflector/optics you end up with a very wide beam of 120 deg+
If you only need 60 degrees then that beam will be 4 times as intense.

 

[Codiak]

If you use it with no reflector/optics you end up with a very wide beam of 120 deg+
If you only need 60 degrees then that beam will be 4 times as intense.

The HD video does very well in low light situations and I could always double the leds.

What I really like is the lumen output is as good as the TerraLux's but much smoother then my current diffusers (and I'm losing a full F-stop do to the material)

You were spot on when you said the sst was for video!

And too think, I'm underdriving the beast at only 2.8Amps

So I have a couple desisions to make before I leave for the cruise this weekend.

1) Do I rush to double the Amps? (no driver on hand fedex would double the cost) No... can I expect the output to double?

2) Do I rush to seal the LED in an air pocket or leave the dome exposed to water?
I'd asked about this in another thread and someone thought water pressure in contact would be an issue and damage the LED. I'm not really sure the LED under air pressure takes "less" damage than water. So do I risk it and experiement? I've dived with flooded LEDs before so whats the diff?

3) Is the LUMEN output of the SST-90 noticably better than the SST-50?
Is it just as wide a beam?

 

[Packhorse]

1. If its a SST-90 then yes you may get close to double the output. If its a SST-50 then no. You will get a little more but not double.

2.DONT expose the LED to water.
Exposing it to air pressure is fine. There is no air in the LED to compress so there will be no movement and no damage.
3. The SST-90 has twice the lumen of the 50. Beam angle is the same although due to its larger die it cant get quite the hot spot the 50 can.

 

[Codiak]

2.DONT expose the LED to water.
Exposing it to air pressure is fine. There is no air in the LED to compress so there will be no movement and no damage.
.

Since I can be dense at times. The dome in direct contact with water = bad idea?

 

[Packhorse]

Yes I agree on all counts.:nana:
Just kidding!!

But yeah, water on the dome may not be all that bad. But the real issue is can you guarantee that the water will not get past the sealant?

 

[Codiak]

Yes I agree on all counts.:nana:
Just kidding!!

But yeah, water on the dome may not be all that bad. But the real issue is can you guarantee that the water will not get past the sealant?

We both know water will get everywhere sooner or later, but yeah liquid electrical tape then a solid layer of molding plastic should do the trick.


I'd love to seal the damn thing, but the sst-50 mounted on the britelumens heatsink is 1mm too tall, preventing the glass cover plate from laying flat. So it's either remove the dome or expose it.

At least this go round anyway.

 

[gcbryan]

Wouldn't it be easier to just grind down the heatsink by 1mm?

 

[Packhorse]

Sounds like a perfect excuse to buy a lathe

 

[Codiak]

Wouldn't it be easier to just grind down the heatsink by 1mm?

Perhaps,
If I had time and my lathe wasn't buried in long term storage.

This is all a test run anyway so it's not a big deal...
I'll be documenting the final design when I'm done if for no other reason then I will have some fabrication I'll need to hire-out.