Overread
Hunting birds with a canon
http://farm2.static.flickr.com/1259/5150174018_597d82a5db_o.jpg
f13, ISO 200, 1/200sec
Taken with canon 400D, MPE 65mm macro - lighting Canon Twinflash!
First off this is not my own original idea and for a far more in depth discussion on the specifics of the method I am emulating I recomend you have a read here:
Juza Nature Photography Forum • View topic - Concave Flash Diffuser Test
That might look complicated, but the theories make some sense when you think about them. So in the quest to lose the harsh highlights seen on insects when using flash I created the following rough design:
What you see there is incomplete at present, but is sufficing as a basic working model. You have the curved plastic caps for the diffusers secured to the ring of cardboard and held to the flash with sticky tape.
This curves the light, but the diffusion is still incomplete as the actual area of the light source is not made much larger -so we add the curve of paper. This is currently two sheets of regular plain white paper held together and just stick with a few tabs of tap to the bracket holding the flash heads.
Further if you look at the heads themselves you'll see that one is slightly higher than the other - using a kaiser flash mount. This is something that is important when using these flash heads as they make the face of the unit longer and so added height helps to distance them from the setup. For a 1:1 shot its not that bad (as seen above I've only one kaiser at present) however by the time you are at 5:1 things get a lot harder to work with because of the short working distance.*
As you can see even with an incomplete setup (no Vellum paper for diffusion - no breakup of the two layers of paper and no silver foil on the inside of the diffuser sides to help reduce light loss) the amount and nature of the diffusion has certainly reduced the effect of the harshness of the light and you can see for yourself that the shell of the insect does not have the bright highlight marks prevalent over the whole shell - there are a few spots, but I hope that slight enhancements to the main method will eliminate these as well.
I'll be interested to hear others thoughts on this and other flash diffusion methods with the twinflash unit as well as other lighting setups of course. Note that this method can be well used with a single speedlite flash and one curved cone of light onto the paper diffuser (infact currently my single 580EX2 tests area little bitter than this at present).
* note that this also requires a different size of paper to be used since the paper sized for 1:1 needs to be physically longer, whlist for 5:1 it has to be shorter.
