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Here's a MrCrouse Mace of Doom Small-Sun ZY-A630 flashlight host with a shortened 70mm Kimunor 500mm telephoto lens modified into a beam expander attached. The 500mm telephoto assembly is about half of its original length by unscrewing two sections (one tube on the input and one tube from the output) to make it shorter and the output PCX was then by necessity replaced with a shorter focal length lens, but it works great! As an awesome bonus, the adjustable aperture iris inside removes the wide optical artifacts which look like wings too, another bonus is the diameter of my Mace of Doom heat sink is an exact fit to the ID of the telephoto tube. I am very happy with this mod due to the reduced divergence of a ordinarily high divergence multimode 6 watt NUBM44 445nm diode to better than that of a 532nm DPSS laser, as well as the beam being cleaned up so well.
The telephoto tube could be left its original length and work without replacing its lens, but I found the tube needed to be a few inches longer to be able to focus to infinity, so I shortened it instead and used another much shorter focal length 70mm diameter lens, which I seated deeper inside the tube against the end of the flair in the tube where it transitions down to a smaller neck. Because the end tube with the original lens holder was removed, I had to put one wrap of electrical tape around the edges of my lens and then just tightly push it into the tube. Alternatively, I suppose I could just put some rubber cement around the edges of the lens, or better yet, find a rubber ring which can compress a little and insert it down the tube against the lens to keep it in place.
To explain how this works, all I do is adjust my G2 lens on the end of the pointer heat sink out of focus enough that it puts out a wide spot which when going through the PCX lens on the end of the tube collimates it to infinity focus, when adjusted with the zoom. There is only one lens inside the telephoto tube, just the one on the end I replaced with a shorter focal length one. This isn't a classical expander setup which uses a fixed focal length concave expander lens coupled with a PCX lens on the end, you don't need to use an expander lens when you can just adjust your G2 (three element lens, or what have you) out of focus so the beam expands larger and larger as it travels forward from it. When adjusted out of focus, the G2 lens is doing the exact same thing a concave lens does and because I can adjust how much the beam spreads, this allows me to make the spot size match the diameter of the collimating lens on the end of the tube. When used this way, think of your G2 as acting like an adjustable focal length concave expander lens, which of course it isn't, but in effect it works that way.
The ebay link, below, shows a 500mm telephoto lens which looks much like the same as the model I have, there are others much like the one I used which are near duplicates to be found on ebay under various manufacture names which would also work, but some of them also have a small lens inside near the input (camera end) which would need to be removed, but most are very simple and only have one lens in them. The thing which makes them work for us is if you defocus the output of your laser pointer lens you can adjust its spot size to match the aperture or output diameter of the collimation lens and use the telephoto units built in zoom telescopic focus mechanism to be able to reach infinity focus. Since the Doom of Mace heat sink has a clear path to slide in or out of the tubes ID, this gives some extra focal length adjustment play (in addition to the zoom focus built into the tube) which makes finding the right focal length PCX lens much easier.
Kimunor 500mm Telephoto Lens for Canon Pentax Minolta Mounts | eBay
Edit: I bought this Kimunor at the above link and it did not have the same construction as the one used with my Mace of Doom host and the tube on the end did not have a seam to unscrew the end lens assembly and hood from the focuser as well as another lens inside the tube just before the iris, seems there are variations with their 500mm units. Not that one this won't work with some modifications to it.
And another one which looks like it might be nearly the same: http://www.ebay.com/itm/five-star-1-8-f-500-mm-manual-focus-lens-/181855278267
Below, although the photo on the left is a little out of focus, it shows the terminus spot when the iris adjusted to remove the wings, the right side photo shows how terrible the wing artifacts are when they are not clipped by the iris.
Above, even though the photo's are not identically centered, I think you can see there isn't any splatter hitting the house on the left when the iris is adjusted to cut off the wings from leaving the tube. I have checked with a laser power meter to see the difference in output power between having the wings cut-off or allowing them to leave and the difference is less than 10 percent, not a small amount, but then not a huge amount either and the beam looks oh so much better when clipped.
Above, 5+ watts of output from a NUBM44 445nm laser diode with the wide side of the beam facing the camera. When this photo was taken the northern lights were out fairly brightly, nice photo, but I forgot to close the iris to cut off some of the wings you can see as a haze in the photo near the end of the beam! The output is still more of a rectangle than a spot, due to being a multimode diode, but it looks great to me. I am not using the full possible expansion of my 70mm PCX lens, more like 40-50mm when the iris is adjusted to remove the wings. As you can see, the northern lights were out that night
Edit: For those of you who are also interested in using this setup for burning:
The closest I can adjust the focus into a fine spot which is only 2-3 mm wide for burning with this setup where the expander is located on the heat sink, as shown in the photo, is about 7-10 meters, when the zoom is adjusted as close as I can get the focal point to be, but if I move the telephoto assembly/tube to the far end of the heat sink, about an inch and a half further out, I can focus to a fine 2mm spot much closer to only 3 feet away.
If I move the tube as close to the host as I can get it to where about 1 inch of gap remains (which is where it bottoms out against a collar inside the tube), I can adjust the focal point to be much further away, perhaps 100 feet or more away (yet to be tested at night) but then I cannot reach infinity focus when solely adjusting the zoom collar on the tube, I would need to reposition the tube to be able to do so. The good news is the tube is tight enough against the heat sink that you can just use the pointer this way without needing to permanently secure it to the heat sink, but in time I expect the uber shiny finish on your heat sink will be removed sliding it in and out like that.
Also, when the focus is adjusted close in, far before infinity focus is reached, you cannot get rid of the wings, I can only use the iris to block the wings when close to infinity focus with one exception, when the tube is pulled all of the way out close to the end of the heat sink, then the iris will remove the wings, I don't understand why yet. If anyone else wants to duplicate this on their own Mace of Doom, the end focus cap must be removed first, otherwise it can block the expanding beam when adjusted out of focus to have the spot match the diameter of the collimating lens on the end.
The OD of my Mace of Doom heat sink (unpainted aluminum) is slightly less than 47mm wide, or 1.85 inches diameter and has about 2.5 inches or 63mm of length exposed to slide the tube around on. Having a 6 watt output laser diode in a host which uses 18650 batteries is pushing them hard, every time I use this laser for a few minutes the batteries are always draining fairly quickly. While a couple of these batteries will work and last long enough to get your heat sink quite warm to the point maybe you ought to give it a rest anyway, I recommend using this diode in a host with no less than 26650 batteries, 32650's even better, or you will be swapping the batteries out before the next time you use it again for full output, I was surprised to find my batteries had drained to 2.7 volts each the last time I used this laser, far lower than these batteries probably should be allowed to drain down to.
To explain how this works, all I do is adjust my G2 lens on the end of the pointer heat sink out of focus enough that it puts out a wide spot which when going through the PCX lens on the end of the tube collimates it to infinity focus, when adjusted with the zoom. There is only one lens inside the telephoto tube, just the one on the end I replaced with a shorter focal length one. This isn't a classical expander setup which uses a fixed focal length concave expander lens coupled with a PCX lens on the end, you don't need to use an expander lens when you can just adjust your G2 (three element lens, or what have you) out of focus so the beam expands larger and larger as it travels forward from it. When adjusted out of focus, the G2 lens is doing the exact same thing a concave lens does and because I can adjust how much the beam spreads, this allows me to make the spot size match the diameter of the collimating lens on the end of the tube. When used this way, think of your G2 as acting like an adjustable focal length concave expander lens, which of course it isn't, but in effect it works that way.
The ebay link, below, shows a 500mm telephoto lens which looks much like the same as the model I have, there are others much like the one I used which are near duplicates to be found on ebay under various manufacture names which would also work, but some of them also have a small lens inside near the input (camera end) which would need to be removed, but most are very simple and only have one lens in them. The thing which makes them work for us is if you defocus the output of your laser pointer lens you can adjust its spot size to match the aperture or output diameter of the collimation lens and use the telephoto units built in zoom telescopic focus mechanism to be able to reach infinity focus. Since the Doom of Mace heat sink has a clear path to slide in or out of the tubes ID, this gives some extra focal length adjustment play (in addition to the zoom focus built into the tube) which makes finding the right focal length PCX lens much easier.
Kimunor 500mm Telephoto Lens for Canon Pentax Minolta Mounts | eBay
Edit: I bought this Kimunor at the above link and it did not have the same construction as the one used with my Mace of Doom host and the tube on the end did not have a seam to unscrew the end lens assembly and hood from the focuser as well as another lens inside the tube just before the iris, seems there are variations with their 500mm units. Not that one this won't work with some modifications to it.
And another one which looks like it might be nearly the same: http://www.ebay.com/itm/five-star-1-8-f-500-mm-manual-focus-lens-/181855278267
Below, although the photo on the left is a little out of focus, it shows the terminus spot when the iris adjusted to remove the wings, the right side photo shows how terrible the wing artifacts are when they are not clipped by the iris.
Above, even though the photo's are not identically centered, I think you can see there isn't any splatter hitting the house on the left when the iris is adjusted to cut off the wings from leaving the tube. I have checked with a laser power meter to see the difference in output power between having the wings cut-off or allowing them to leave and the difference is less than 10 percent, not a small amount, but then not a huge amount either and the beam looks oh so much better when clipped.
Above, 5+ watts of output from a NUBM44 445nm laser diode with the wide side of the beam facing the camera. When this photo was taken the northern lights were out fairly brightly, nice photo, but I forgot to close the iris to cut off some of the wings you can see as a haze in the photo near the end of the beam! The output is still more of a rectangle than a spot, due to being a multimode diode, but it looks great to me. I am not using the full possible expansion of my 70mm PCX lens, more like 40-50mm when the iris is adjusted to remove the wings. As you can see, the northern lights were out that night
Edit: For those of you who are also interested in using this setup for burning:
The closest I can adjust the focus into a fine spot which is only 2-3 mm wide for burning with this setup where the expander is located on the heat sink, as shown in the photo, is about 7-10 meters, when the zoom is adjusted as close as I can get the focal point to be, but if I move the telephoto assembly/tube to the far end of the heat sink, about an inch and a half further out, I can focus to a fine 2mm spot much closer to only 3 feet away.
If I move the tube as close to the host as I can get it to where about 1 inch of gap remains (which is where it bottoms out against a collar inside the tube), I can adjust the focal point to be much further away, perhaps 100 feet or more away (yet to be tested at night) but then I cannot reach infinity focus when solely adjusting the zoom collar on the tube, I would need to reposition the tube to be able to do so. The good news is the tube is tight enough against the heat sink that you can just use the pointer this way without needing to permanently secure it to the heat sink, but in time I expect the uber shiny finish on your heat sink will be removed sliding it in and out like that.
Also, when the focus is adjusted close in, far before infinity focus is reached, you cannot get rid of the wings, I can only use the iris to block the wings when close to infinity focus with one exception, when the tube is pulled all of the way out close to the end of the heat sink, then the iris will remove the wings, I don't understand why yet. If anyone else wants to duplicate this on their own Mace of Doom, the end focus cap must be removed first, otherwise it can block the expanding beam when adjusted out of focus to have the spot match the diameter of the collimating lens on the end.
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