Substitute for ring flash
 

Here is a simple lens torch I made to illuminate subjects on my 60mm macro lens, as I found I often blocked out the light when closing in on the subject.

You require a small soldering iron and to be able to solder.:)

To make it you require enough 3.0 volt LEDs to cover the edge,mine has about 60, buying them in a bulk pack they are very cheep, I used ultra bright white LEDs , you have a little white balance to adjust in the shots but they are normally very good.

Stiff plastic, card could be used but plastic is more durable.
I recommend you experiment to get the correct fit and length of tube, make it as long as you can, when looking through the viewfinder it should not be in view

Copper wire, I used a single strand of mains twin and earth 1.5mm

A battery holder.


Method

1: cut a strip of the plastic about 2 inches wide, depending on your lens it may require to be wider but you can check later. Wrap the plastic around the end of your lens like a lens hood. Cut it length so that its just a nice fit without falling of, you can use a bit of tape to hold it in a tube shape while you get it right.

2: put batteries in your holder and find out which way round the LEDs work, the only work connected one way. Note down the connection.

3: Using a bit of single strand copper wire make one ring that fits inside the plastic tube, and one that fits round the outside of the plastic tube, solder the ends of the rings, they can be a slightly loose fit but assembly will be easier if they are good.

4: Fit the battery box, mine had 2 wires under it, make small hole for them to go through, bend one wire up towards the front the other towards the back. Fit your copper rings to the inside and outside connecting one to each end of the batteries, install the batteries for a few minutes to test an LED, slip it over the end so that one wire goes each side of the plastic and it should illuminate, now all LEDs must be mounted in the same manner, either long wire inside or outside depending on how the first one worked.

5:remove the batteries, start fitting the LEDs side by side, soldering each one as you go, trying to keep them all pointing straight forward, clipping the excess wire off as you procede.

Your done, simply install the batteries and they will all light up, the batteries will last a long time, slip it on the front of your lens and off you go.

I hope the images help illustrate the idea and demonstrate the light pattern, its nice full flood that gets into all the wee spaces reusing shadow.

Have fun, Bob

OOOh! I like it Bob, that's a brilliant idea and you wouldn't have to wait for it to charge. I know what my next project is going to be.
All I have to do now is source some Led lights. I can't wait to have a go.
I could take apart all my garden lights and nick one bulb out of each one:D but I don't think Mario would be very happy. LOL!

Parts
 

This link to Fleebay may help 50 for £5 ultra bright 3.volt Leds

http://cgi.ebay.co.uk/50ps-10mm-1500...d=p3286.c0.m14

Bob

Thanks Bob the cheapest I could find was 49p each.

Bob, what is the difference in 10mm 2500mcd and 10mm 1500mcd, the 2500mcd are in a pack of a 100.

mcd
 

Hi Christine I'm sure the MCD is the output

"The unit of measure commonly used to describe LED intensity is the millicandela (mcd), 1000 millicandela equals 1 candela.

10 mm is quite big and 50 would probably do it, but if your making 2 :)

I think you have the bug :)

Bob

Thanks Bob, I will go for the 50 of the 2500 if they are brighter, I counted how many you had in the one you made and thought I would be short.

Looks fascinating Bob. I wish I'd have seen it before I bought my ring flash - much cheaper, and I would imagine just as effective.
How about a refinement - 2 switched circuits, one for each semi-circle of LEDs - so you can have modelling light if required?

LEDs
 

Christine, my LEDs are 5mm so you will require less if using a bogger diameter, your battery will not last quite so long with the brighter output but LEDs take hardly any current so I'm sure they will last a long time anyway.

Gordon, good idea it could be that each alternate one is iluminated to maintain the ring pattern. I doubt very much if this will be anything like as bright as a flash gun\ring flash but I found it delivers a softer more efective light for close macro, and when you move in close if the subject is live, theres no bright sudden flash to scare it off.

Bob

I think you'd need some asymetry to the array - what I had envisaged was directional light so that you could introduce some subtle shadowing to give a more 3D feel than the ring flash light does. (My ring flash can do this - you can turn up or down each side, or have even shadowless lighting, but it is a bit flat)