Unexpected results with aspheric Mag

:shrug:I put a 50mm/35mm aspheric lens in a 2C with Magled (removed lens

and reflector). What I got was about a 6 foot circle of light from about

5 feet away, in other words, a flood. Where did I go wrong?

The emitter is too close to the lens. Unscrew the head until it focuses, or put the reflector back in, althought that will make a difference in the beam.

You need to focus it. If you can't get it to focus, than you need a different focal length. I know with my mags incan mags with a Terralux LED drop-in I have to keep the reflector in to push the LED down so it's far enough away from the lens to focus properly.

flange938 said:

:shrug:I put a 50mm/35mm aspheric lens in a 2C with Magled (removed lens and reflector).

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For a 35mm focal length lens, the lens must be 35mm away from the LED die. Adjust as necessary.

Leave the reflector in.You will have to cut the lip off of the reflector if you want the bezel ring to fit without a gap.

Thanks, guys . I'll try some of your suggestions.

ZMZ67 said:

Leave the reflector in.You will have to cut the lip off of the reflector if you want the bezel ring to fit without a gap.

Click to expand...

pic of how much to cut off

f22shift said:

pic of how much to cut off

Click to expand...

just the flat lip, not any of the curved reflector part.

I tried holding my lens above the light and it only begins to focus with a gap of about 3/8". Not really practical. Putting the reflector back in seems to negate the whole point. Could I have received the wrong lens? I asume the dimensions of Maglites are consistent as are the Magled. I am at a loss
to explain why my results are so different. I tried my other leds (K2 Diamonds) and the results were the same.

Not to ask a stupid question, but... Is the lens installed with the convex side out?

Yep, sure is.

flange938 said:

Yep, sure is.

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I assume you ran the head up as far as possible and are still lacking 3/8 inch.

This sounds about right if you removed the reflector, because the spring loaded post is all the way up without the reflector, so I doubt you have the wrong lens.

Put reflector back in and make sure you can get a nice small hot spot.

The hotspot will be a small sharp square image of the LED die like the ones you see that others have posted.

Once you are sure that everything is ok, there are THREE ways to proceed.

1. Leave the reflector in and ignore the rings. The light that hits the reflector wasn't going to hit the lens anyway, so you won't loose any of the hotspot (though some don't like uneven rings of light this creates)

2. To avoid the rings with the reflector still in place, you can simply paint the reflector FLAT BLACK with some spray paint (you should rough up the inner surface with course sandpaper first, because even a flat black surface reflects a little if it's smooth).

3. To avoid the need to use the reflector at all, you can simple use your finger to push the lamp mounting post mechanism down a half inch or so, and then squirt some hot melt glue into the works to lock it in place so it doesn't pop back up and mess up the focus.

Leaving the reflector in place and painting it black, leaves the angled bulb-up/bulb-down focusing mechanism on the back of the reflector in place, so once you find the rough focus, the light will run through the full wide-to-spot focusing range in a single turn of the bezel head.

Taking the reflector out and adjusting the post height then locking it down with glue, disables the up-down post focusing mechanism, giving the light a slower 'micrometer' style focusing adjustment. Focus can still be adjusted over the full flood to spot range, but you will have to turn the light's bezel head turn by turn up through several 360 degree turns to get the same range you get with the reflector in a single turn.

Hope this helps.

Luminescent said:

2. To avoid the rings with the reflector still in place, you can simply paint the reflector FLAT BLACK with some spray paint (you should rough up the inner surface with course sandpaper first, because even a flat black surface reflects a little if it's smooth).

Click to expand...

Thats exactly what I did on mine. I can post pictures if it helps any.

Beer said:

Thats exactly what I did on mine. I can post pictures if it helps any.

Click to expand...

Can you post beam shots?

oh man dont toss out all the light hitting the reflector, that is like 40%, its almost everything that would normally be the spot, it will reduce your "total lumens" to send it into a black hole.
at the least get some glow paint on it, so the light goes into something usefull :-( or use GLOW vinyl sheeting, which can be removed again if you change to next weeks miracle.
http://stores.ebay.com/READY-SET-GL...icker_W0QQcolZ4QQdirZ1QQfsubZ11QQftidZ2QQtZkm
this guy sells the vinyl glow, the adhesive on it is POOR, but it will stick and hold in place, and still be removable.

i used one of them hotlips heatsinks, it will resess far enough to get full focus by screwing the head on and off (so to speak).

are you guys getting wide to spot focus with the original CAM reflector in the mag?

What I personally have done with some of my aspheric stuff is to remove the reflector, then paint the entire inside of the light with white paint -- this will create some degree of diffused reflection (rather than "rings") that provides a useful amount of spill. Another option if you are building a light from scratch is also to use a Cree XR-E LED as opposed to a SSC, as the Crees will emit mroe of their light forward (into the lens.)

The ideal solution, rather than waste any of the light going to the side, would be to mount an elliptical reflector with the LED at one focal point, and the lens at the other -- this is the way a typical projector works, and as a result, ALL of the lumens end up being focused.

VidPro said:

oh man dont toss out all the light hitting the reflector, that is like 40%, its almost everything that would normally be the spot,

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The Mag LED conversion is designed to be used with the reflector, so it uses an LED which throws more light to the sides, but there are other drop-in conversion LED's available with domed lenses having the more standard 'lambertian pattern' that will send more light through the lens.

Most folks who do their own custom aspheric lights are using CREE or Rebel LED's, both of which seem like a good choice. In addition to the better light distribution, these LED's have about twice the luminous efficiency of the original Luxeons used in the Mag drop-in.

Light is also lost because the aspheric lens has a very low F-Ratio and is not multicoated, so the lens looses efficiency at the edges because that light arrives at an angle of 30 degrees or more and a lot of it bounces off.

The 'lambertian pattern' used by Rebels and the even more center weighted pattern of the CREE help overcome this by putting more light in the center area of the lens.

Despite all of the above, even with the stock Mag drop-in LED conversion, the aspheric lens is so much better at focusing than the stock reflector that the increase in throw of these lights is really spectacular.

I see this will be a bit more compllicated than I thought, I'll try a lens modification and see what happens. the only other dropins I have
are the Diamond K2's in white and cyan.

flange938 said:

I see this will be a bit more compllicated than I thought, I'll try a lens modification and see what happens. the only other dropins I have are the Diamond K2's in white and cyan.

Click to expand...

I didn't mean to make things more complicated than necessary.

Lot's of folks have had pretty good results with the standard mag drop-in.

Remember the unmodified Mag using the Mag LED drop-in is already a half-and-half proposition anyway.

About half the light hits the reflector and forms the spot, and the other half just goes through the front lens to form the spill.

The aspheric configuration just reverses this.

So you see, with the aspheric lens in place of the normal flat front lens, the aspheric lens will have about the same amount of light as the reflector did to work with, it's just using the other half from what would normally form the spot.

The aspheric lens is better at focusing the light, so this 50% goes a lot farther.

When you want spill only you just crank the bezel so the LED is inside it's normal focus (very close to the lens), then almost all the light goes through to form a nice big uniform flood.

A LED with a narrower pattern will be even better, but the Mag drop-in should be still be pretty impressive compared to the standard Mag once you get everything lined up properly.