I have planned for a while to be able to take photos of liquid splashes and whisky pouring. Here are my notes so far.
Any camera will do as long as it has a manual setting ie. you need to be able to set shutter aperture and ISO independently. Always shoot tethered if you can. Find out the Xsync speed of the Flash unit(s) you have – usually 1/125 – 1/200 (eg for Canon 580EX II User Guide , Manual and example) . It is worth investing in two flash units and a hot shoe radio trigger. The best value ones are YongNuo Flashguns for under £50. 3 types flashes Normal strobe (flash duration long); Speed lites – can produce very short duration – less than 1/20,000 if used at reduced output – see here for Canon 580EXII and here for the technical side; Specialist flash units with a really short flash duration. Eg. Einstein $500. Using Speedlites: – Half press then shoot. Slightly darker at top because more light at bottom. Sample – use speed light at 1/8th power and shoot at f16 1/200th. Try 400 iso. Never go higher than 1/8th power. Use same power for both speedlites as colour cast changes at different outputs.
This is the best resource I have found and worth the money: High-speed photography for beginners by Pascal Bovet.
This shows the basis of a two flash set-up (and a useful tip with plastic bags too):
Lastly, how to create bottles that ‘pour’.