Digital Slave Flash uses

[RedRoxx44]

Obtained two relatively inexpensive slave flashes from Digital Concepts, one small and one larger. Wanting to expand my cave photography a bit. Trialing them in the house a little disappointed in the illumination, my onboard camera flash seems stronger than either one of these. However they do consistently fire with the camera flash and not with the sensor, so I guess that is good. I mounted one on the hot shoe of two cameras and couldn't get it to work that way---and yes I set it to the "normal" mode.
Any suggestions as to making them work better other than trial and error?? And reading the directions-- ;)

[JoelHazelton]

However they do consistently fire with the camera flash and not with the sensor, so I guess that is good.

I'm not sure what you mean by this... Do you have light slaves and the flash from your on-camera flash triggers the slaves?

The best way to use off-camera flashes is with radio slaves, Pocket Wizard makes some good ones. The light slaves are crappy and unreliable. I suppose that's not so bad with cave photography since you've generally got several opportunities for a single shot (rather than sports photography for which they're more often used).

Are you using manual or auto settings on the flashes? It's difficult to get a good effect unless you can set them just like you would adjust the settings on your camera. Sunpak makes some good flashes that allow fully manual settings.

A good rule to make a subject "pop" with two slaves is to set one in front of the subject at an angle (not directly in front, this makes lighting flat) and one behind to backlight it. Set your camera's aperture and flash sync to that of the main flash in front of the subject. Set the backlighting slave one or two stops brighter than the front-lighting slave. This adds a strong 3-D effect to the shot and really makes it pop.

[RedRoxx44]

They are light slaves. I looked at Sunpak but a little too sophisticated for my level. One is small and has only auto settings, the second one is larger and can set for F-stop etc. Since they are going to be in a rough environment I did not want to spend too much money until I get the hang of it. I have a small tripod I will bring also.
Thanks for the suggestions. I hope I can better photograph some of the larger rooms. Now the challenge is packing the equipment in.