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Discussion Starter · #1 · (Edited)
Given all the other "here is my light" threads I thought I should join in :)

Here is my 1st attempt. It is a very simple lash up so I could experiment with beam patterns, a Q5 star stuck in a 2mm stop end, dx driver and dx lens all tie wrapped to a 4 AA cell pack. Total cost around £12....


Not exactly the most professional build but it proves the point and it is the obligatory beamshot that is probably of most interest......



you will notice that it is a broad oval but with a centre spot. Pretty much what I wanted to give a nice wide flood close up but the spot giving a decent reach.
Light to the wall is about 1m and the oval is about 1m wide (ie. very wide) but the spot is about 30cm high.
On the road this is fine, off road the single Q5 is not really enough but it is still useable, particularly if supplemented with a tesco AA on my helmet.
The great thing about this is that very little light is wasted in the sky and I don't worry on road about annoying cars even when the spot is aimed as far down the road as it will go.

To get this beam pattern I modified a oval lens from DX (SKU4600) which is normally something like 15x45deg oval. I polished of the bottom 1/3 of the Fresnel pattern to convert that part to the spot while retaining the oval for the rest. Two lenses in one :thumbsup:



Food for thought anyway.....

BR,
Toby
 

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aka RossC
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936 Posts
Nice work on the optic modifications It give a very interesting beam pattern.
So does the smoothed section produce the spot? If so, how do you get the oblong shaped section?

As far as double pics... If you go in and edit your post, you will probably see that there is a link for the image addresses at the bottom of your post. Sometimes after the images are uploaded and you hit the paperclip symbol and insert all, it puts them all at the end of the thread.
 

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Discussion Starter · #4 ·
Ah, thanks for the info on the images, I've now managed to delete the extras :)

the original lens is actually a spot lens by design but the manufactuer adds the freznel (ridges) on the front to turn it into the oblong shape. Basically the oblong is the same height as the spot would be but spread out horizontally.
Polishing off some of the ridges then turn that bit of the lens back to its original spot. So I now have part oblong and part spot.
If I polished off all the ridges I should get just a simple spot light.

I was interested to see that to get the spot at the top of the beam pattern (as shown) I had to put the lens with the polished bit at the bottom. It must be inverting the beam.

Toby
 

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Lets RIDE!
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1,548 Posts
No images (or links to images) on my screen.

Sometimes if I'm not signed in I see links instead of images. But right now I am signed in, and see nothing :-(

Have to admit I'm confused on how to place images in my posts. Embedded in the text vs. all at the end, and how to get them in the proper order. When I have posted photos, they've always shown at the end.

JZ

edit: I see a "how to post pictures" thread has started...I'll check that out.
 
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