Bob I have just received the leds and will be doing the build sometime next week when I have time, I can't wait to see how they work.

Excelent, you can test one out by attaching it to a battery of course, and now that natural light is starting to fade a bit you will get even more use from it, experiment at night taking shots of flowers etc, its good fun :-)

Bob

I decided I couldn't wait until next week to start this project, so here is what I have done so far.

I bought 50x 10mm Leds off ebay. Total cost £4.95 with postage.
Spare 2 core Speaker wire.
Black gaffa tape
Chrome Tape to use as a reflector.
The cardboard tube from an empty gaffa tape role, this fits nicely around the Canon 100mm Macro.
A straight Pin
Long nose pliers.

Photo 1.
Mark and pierce holes with the pin 11mm apart in each side of the speaker cable and push the positive pin though the positive side and negative through Negative,

Photo 2.
Align all LEDs so they are the same height and bend the pins over so they don't touch each other.

Photo 3.
Put a small strip off gaffa tape over the bottom set of pins to give some insulation.

Photo 4 & 5
Cover cardboard tube with black gaffa tape on the inside and outside.
On the top edge put a small strip of chrome tape to act as a reflector.
Wrap around the LED's so the bulb is resting on the reflector and hold down with more gaffa tape.
Cut a 1/2" wide piece of cardboard the length of the leds plus a little overlap, cover this with chrome tape. Wrap this around the outside of the bulbs and pull tight and join. (This is the outside reflector).
Finish off with Black gaffa tape to hide all the pins and attach the battery holder. I have yet to do this as I have only borrowed one from something else.

I think I need to do some more modifications, if I go to close to a subject I get a doughnut effect so the subject is not lit up, to far and it is only useful as a fill light.

Christine a very inventive solution well done for lateral approach to soldering. I can see why you are getting the illumination problems. If you look at my build you will see that each leg goes each side of the tube, there were 2 reasons why it was done that way, one was to isolate each contact, the other was to ensure that the LEDs were mounted pointing directly forward, looking at your mount they are pointing outwards away fron the mount, giving you the wrong pattern. Is it possible to straiten them up.

Bob.

Bob, on the finished ring the bulbs were facing forward, I put a tight sleeve with reflective chrome tape around the outside of the LEDs to straighten them up. That wasn't the problem what I found was if I went any closer than 8" the center of the frame wasn't lit up, it was in shadow.

I only had time to post 5 photo's on Thursday, I didn't realize I hadn't posted the finished ring. Now that my Archery outdoor season has finished I am going to see whether I can get a better angle maybe pointing inwards slightly to make a snoot shape with two rows of lights..

Finished light
 

Hi Christine, the finished unit looks very good its just a pity the results are not as expected. I think it must be down the actual LED lens, mine are smaller in diameter and the light pattern is very useful. I must have been lucky mine worked first time, there are newer leds that give even more light but are fairly expensive, I'll see how the budget goes :)

Bob

Bob, its a shame they don't seem that bright with 6volts, I did try briefly with a 9volt pp3 and they are very bright but I don't want to burn them out by using the wrong voltage. I am still thinking of how I am going to make the snoot shape. I don't want to make it out of cardboard it will be to flimsy. I will get there.

I have now made Mark 2.

I stripped everything down and carefully parted the wire so as not to break the pins. I ended up with one wire all positive and one wire all negative.
I decided to use the original tube because it fits the end of the lens nicely. I then put one wire with one set of legs on the inside of the tube and one wire outside, and taped them in place. I put a hole in the tube and pulled the end of the wire through ready for connection.
I slightly tilted the bulbs inwards to allow me to get closer to the subject without any doughnut effect.
All now works brilliantly accept for one major problem the white balance I can't seem to correct this either in camera or in software without losing all colour. :(
Example below.
1st Photo finished ring
2nd photo with LED's
3rd photo with my original home made ring flash using the onboard flash

Christine,

Maybe worth a post re your White Balance problem as a 'HELP' in the Photography Forum in the hope of attracting attention.

I just had a look in Bobs gallery and see he uses a Nikon D300, and I cannot help as I do not have any LEDs.

Don