If you've been following Strobist's blog, you know he's a big Nikon user. From David, I learned a few things about the Nikon SB-26's that interested me enough to buy three used ones from Adorama to see if they would work properly when triggered optically using my Canon 580EX as a master.

Well, the first impressions appear promising.  The SB-26's slave delay mode appears to allow my camera ( a Canon 30D) to meter the exposure before the SB-26 fires.  I have two 430EX's that I intend to use for main lighting, and I wanted to use the SB-26's for background or rim lighting.

Using the Canon flashes In regular ETTL mode (no slaves), the SB-26 has worked flawlessly for me.  With a 580EX as a master, and only groups A and B, the SB-26 still continues to work very well; it's slave delay working almost flawlessly to ensure that it's burst is not picked up during the camera's preflash metering cycle. 

Using group C, however, results in failure, with the SB-26 firing prematurely before the shutter is released.  There is simply too much communication going on between the master flash and the 3 groups of slaves.

My experiments to date only involve me holding the SB-26 in one hand and my camera in the other and taking a shot of the wall in front of me. I'll set up a more useful scenario and post detailed information and results.