In article <1995Aug14.135420.3858@schbbs.mot.com>, bobc@ecg.csg.mot.com says...
>Problem: N90s with SB-26 can't perform wireless TTL. However, it can
>do manual wireless flash.
>Solution: Yes, it is possible. For single wireless TTL flash control, >you'll need another N90s/SB26 or N90/SB25 and a wireless remote trigger >for both camera. Nikon makes this equipment; I just can't remember the >model number. For multiple wireless TTL flash, just add more N90s/SB26.
>For the single flash case, the master camera should have the film in it >and the slave no film. With the slave camera, have an assistant focus >on the subject while the master will trigger the slave when the shutter >is released. Presto! Wireless TTL. The remote salve will fire the >remote flash according to flash to subject distance of the remote flash.

Kinda cute (though expensive) solution to TTL cordless remote... Though
there are a couple of problems. The remote camera should have a film scrap inside for the correct flash TTL metering reflectivity. If the
remote flash camera is placed at too great an angle from the subject compared with the taking camera, the light from the remote (being side-light), will be insufficient and will need to be compensated,
reducing the simplicity of TTL exposure. If the angle is kept small,
TTL remote cords work well instead of double cameras and flashes
(and the sensor is where it needs to be for correct exposure). Also,
when multiple TTL or auto flashes are simultaneously fired, and are not
wired together, uncontrolable flash ratios can occur between them.
Hope this helps.