Originally posted by slipchuck I never tried what you want to do. but I know by playing with the sigma 17-70 macro that when you get that close, lighting (or shall I say lack of) becomes a real challenge. My lenses ability to get real close is only stopped by the lack of light due to the shadow of the lens.
I was thinking I could somehow rig this little unit up which could be triggered by my flash.
not sure how though
cheers
randy
I just bought some of these flash units (5) and have set up two as follows. I
un-hook the stand/cover from the flash unit and turn it around and put it back on. Using a bit of camera case padding foam as a spacer, I strap two of these units to the lens-hood on my 100mm macro lens, using a short length of webbing and a slip-tightening buckle. They can be fired by any small flash on the camera body, and they are quite sensitive.
To improve modelling and give some shadow detail, I swivel one flash to face in towards the subject, and leave one facing straight forward. This gives me F16 or better. I also used this arrangement with a reversed 50mm lens on the front of the 100mm lens.
It is early days yet, but I think this is more promising than the previous lash-up I designed with two full-sized variable power flashes and heavy brackets to hold it all together. I was trying to emulate the manfrotto macro bracket, but the whole thing was too heavy and awkward for hand-holding.
You could actually fit three of these units around the lens-hood if you wanted more light. This would emulate a powerful ring-flash set-up, and probably allow you to reach significant magnification at reasonable apertures.
As always, focussing is difficult, due to the massive light loss at high magnification, but I have the germ of a plan to solve that problem with a light-weight ring-light assembly using 3 AAA cell batteries and high brightness white LED's. Hope this is of some use to you.