Thanks guys for your votes and encouragement. I'll have a think about the theme for this weekend.
Tifosi, I
knew someone would ask me that sort of question. A verbal description, as I haven't got any citrus fruit left to repeat for a picture of the setup:
Take a rectangular glass flower vase and put it on a black cloth. Raise the black cloth on three sides to cut down on stray reflections and also give the dark outside edge to the bubbles.
Take one thin slice of lime, put the centre of the slice on the end of a cocktail stick. Slide the slice of lime into the vase so that it is pressed against the inside front (the side which does not have raised black cloth) face of the vase. Break stick to length to hold lime in place by wedging other end of stick against back inside face of vase. Place camera on tripod so that it is viewing the face of lime slice that's pressed against the glass.
Take flashgun, attach remote trigger cable, a simple single contact one in my case and set flash to manual power. Have flash pointing towards the camera, i.e. illuminating the back of the lime slice, and raise it up (on a stack of CD cases if that's what you happen to have to hand
) so that the centre of the flash aligns with the centre of the lime slice and the centre of the camera view. Really make sure the camera is aligned perfectly squarely to the vase/slice.
Set camera to fully manual exposure, set trigger to max flash synch speed, set aperture to give good DoF at close range, f/14 in this case, small aperture will also create a degree of starburst effect to the catchlights. Set flash to a low power setting, I started at 1/64th max power initially and flash zoom to the widest angle it will go to, which is 18mm with the Metz AF58-1. Set camera focus to manual and ensure focus is on the face of the lime slice.
Fill vase with fresh tonic water, fire off a test shot, chimp, adjust flash power to compensate, repeat until you get it right, it doesn't take long. I ended up with 1/128th power after about 3 adjustments.
Top up vase with another generous splash of tonic to get some extra fresh bubbles, take final shot.
Hope this helps.
Duncan