Wireless Flashes - Do they really work?

[picturetaker1239]

I'm just wondering if anyone has any experience with wirelessflash slave units you might find on ebay. I'm talking about the ones with optical sensors that sence light and other flashes. Not the infared ones. they are roughle 15 bucks on ebay and have a screw in mount for your tripod and a hot shoe sleeve on the top. its a small unit that goes sits under the flash and sets it off. its rated for 60 ft. if anyone knows anything about them or their performance it would be greatly appreciated because I find that long lense skateboarding and extreme sports photography is difficult in low light situations. I'm trying to put the flash in the picture to get proper lumination of the boarder. I hope I'll only have good things to hear!

[another view]

its rated for 60 ft.

Maybe in a really dark interior room you'll get 60', but in the real world - and definately in the situation you're talking about I doubt you'll reliably get half of that. I have used optical slaves before and they're pretty touchy. They can work just fine, but can work just as fine for other people when their flash goes off, not helping your battery life or recycle time of course. The slave has to "see" the flash, and sometimes a piece of aluminum foil (or a white index card) bent into a reflector and held in with gaffer's tape can help that a lot.

Pocket Wizards work amazingly well, but they're also amazingly expensive...