Hints and tips for Mini-Mag LED lens

I personally find that the projected circle of LED light with a lens is way cool. As stated earlier, the Brinkmann Long Life LED started it! I liked the beam it produced and attempted to reproduce it with my new LED converion. This lead to a discovery of an even better, more smoother circle of light than even the Brinkmann. My Brinkmann shows the LED wires quite visibly. My conversion lamp does not at proper circle focus. The beam is slightly brighter with internal shadows when it is out of focus, but a smooth, almost shadow free circle when focused properly.

Another source for lens, other than telescope or binocular eyepieces, is an old security cctv camera lens. The back lens of these srew-on camera lens is the ones you want. Most will screw off with determined effort to recover the lens. There are usually 2-3 lens in this part of the lens. Different beam patterns can be had by using one or two a time. Find the best one for you. Experiment with different distances from the LED. The focal length of these particular back lens works out just about perfect for sitting on top of a 2AA Mini-mag.

To hold the lens to the head, purchase the filter/rubber cap package to get the rubber cap for around $5, or go to another isle in that hardware store and pick up a black rubber 7/8" crutch/chair leg cap for $0.50! Of course the filter cap already has the hole in the top but if your particular lens you find is smaller than the opening, you may want to go with the crutch cap and drill/cut-out your own lens hole. BTW, the crutch cap fits much tighter and deeper onto the head and seems to hold the lens in better. If your lens is a smaller diameter or if even just one of them is, use rubber "o" rings from another isle in that store to space them and/or keep them centered in the cap. Try different spacing of the lens you find. Use "o" rings to space them. Most are air spaced a bit in the camera lens body anyway.

I was fixing to post an image of the beam pattern at 2 foot away, but see that UBB images are not permitted anymore? Sooooo, below is a link to take you to that image. As you can see there is a secondary outside ring of light that helps illuminate the side for that path walking.

4.5 volt w/lens Mini-Mag LED conversion beam pattern

WARNING: After lens conversion, DO NOT LOOK directly into the beam. Serious eye injury will occur if the beam is stared at, at close range.

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by Stargazer:
I personally find that the projected circle of LED light with a lens is way cool. As stated earlier, the Brinkmann Long Life LED started it! I liked the beam it produced and attempted to reproduce it with my new LED converion. This lead to a discovery of an even better, more smoother circle of light than even the Brinkmann. ....
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As I wrote in the other thread you opened for the same topic I made also some experiments with lenses. For this I took the lenses of a magnifying glass (magnification is about 10x ). I got a similar beam like you are showing in your pic. Depending from the adjustment (distance LED - lenses) one could see the wires of the LED or not. Maybe its easier to get such a magnifying glass than the lens of a CCTV cam.

Another thing I tried was the lens of bicycle LED front light. But this lens didn't give such a smooth beam pattern even it's designed for exactly such an application. I think it's a too cheap plastc lens.

By the way: Why did you start a new thread about this topic? It would be much easier for all of us to find all information about a certain issue in one single thread and to discuss it there.

If you want to rename the first thread go to your first post in this thread (the post with which you started the thread) and click on the edit button. Then you can also change the title of the topic!.

I just bought an assortment of 20 lenses for two bucks from American Science and Surplus

I haven't really made anything from them yet, but playing around with them, I have discovered that most of them do a very good job of focusing LED light, and are in sizes useful for small projects from mini-mag on down.

Most of them even modify the wierd and ugly beam pattern from those blue-green 10,000 MCD leds from B.G Micro into something sharp and smooth.

The item number if you are interested is 21332.

Yes, I've been doing test with some lenses from a broken binocular. The results are very good, and I wonder if Luxeon is planning to commercialze a narrower collimator, 0,5º will be perfect instead of the 10º...for certain aplications, of course. The collimator in the LS is very easy to replace, and I think it is possible to see different beam angles in the future. Meanwhile if we need something like that we could try looking for in plastic lenses manufacturers, like the ones which makes collimators for the pointers.
The most intersting thing in having a narrow angle flashlight is the ability to put the light far away, and this is the only way to convince some people that a flashlight is usefull and bright enough...IMO a combination using wide and narrow angle LEDs could be perfect. For better performance the wide and narow LEDs should be switchable, as they disturb each other. In my test I have noticed that the narrow angle is more visible far away if the wide angles are off, and the bright point is no good when you try to see soemthing at 2-3 m.

I started a new thread on the conversion mainly due to the battery issue, as the other thread going used (2) AA batteries where as mine used (1) AA and (1) 2/3 AA. (3) 2/3 AA's would work as well with correct resistor in insulated battery base. Also, I must have missed the lens part of the other thread. Just wanted to share what I had found out with all, and provide another subject for searches in the future by others seeking lens information. In all the LED flashlight reviews I had read on the web, No where had I seen a beam pattern quite like what I got with the lens I found. I had to share that spot on the wall with other Flashoholics.

Another discovery: Old camcorder lens have some very nice and useful lens inside them. I tore up an old lens from a camcorder and in the middle were (2) very useful convex plano lens. These were even the perfect diameter to fit under the screw-on lens cap that is at the very top of the Mini-Mag! They needed to be spaced via "o" ring to give a nice circle of light, but all this fit under the chair leg cap just right. Just some more places to find lens.