Help me set up a macro flash rig
Okay, I have been playing with some manual flash setups for macro photography mainly using some suggestions that Dan Fromm gave me on this forum and some plans and spread sheets that he was kind enough to share with me. I have been playing with the two flashes I currently own and using a flash meter to test. Exposures both on the meter and on a couple of test rolls have been good, so I am ready to finalize the setup for use this summer.
I will use the setup for insect photography in the field and want to (1) avoid harsh shadows and (2) dark backgrounds. So I am thinking of a three flash setup.
(1) Two of these would be used to light the main subject and will be mounted on either side of my lens about 3inches away from the lens axis. I am using a diffuser for each flash. Given that the diffusers lose about a stop of light, I can easily calculate the flash to subject distance if I know the focussing distance of the lens. I have tested this with my SB-28 but need to add another flash for the subject. I am thinking of a SB-27 because it is reasonably cheap and can be used as a TTL slave flash with my SB28 on the rare occasion that I want to shoot humans with my N90s! If you think any other flash would serve my purpose better than the Sb-27, I'd love to hear your thoughts.
(2) For the background, I am thinking of putting my SB-18 flash on a tripod and moving it around independantly of the camera rig. Since unlike the lens to subject distance, the distance from the subject to the background is unpredictable, this seems the best solution. With a GN of 65 or so, and shoothing at an effective aperture of f22, say, I just have to plunk down the tripod about two and a half feet from the background and I am all set for beautifully lit backgrounds whether it is 6 inches or 6 feet behind the insect I am shooting!
Now the trick is to sync all of this stuff. I have the SC-17 and SC-18 TTL cords but for manual flash could just use a Y PC connector to trigger the flashes for setup (1). Ideally setup (2) would be fired wirelessly giving me the maximum flexibility. Wein, Vivitar etc have a number of these accesories which are priced between $20 to $40 but I hae no idea how well they will work. Does an optical slave need to be in the line of sight of the triggering master flash or can it "see" the light at a reasonable distance. This is important because depending of where the background is, #2 can be in front of or behind #1. More cumbersome would be to use a long PC cord and I would like to avoid it if possible.
I am going to be in Chicago in a couple of weeks and was wondering if the Calumet showroom would be a good place to check out these slaves first hand. Their website is pathetic but is the showroom better. Any other shops in Chicago that would be good for off camera flash stuff?
Sorry this is so long. Any comments, thoughts and suggestion on any aspect of my planned flash setup would be appreciated.