Originally posted by WMBP (snip) P-TTL does not seem to work very well. I get too many photos with people whose eyes are drooping that Nikon and Canon photographers don't get. (snip)
Virtually all modern digital SLR cameras use a pre-flash, Will. Older Nikon digital cameras (D100, etc.) used D-TTL and newer Nikon digital cameras (D50, D70/s, D80, D200, D2x, etc.) use iTTL, and both of these flash modes (D-TTL and iTTL) use a pre-flash to determine exposure. Older Canon digital cameras (T90, etc) used A-TTL, newer Canon cameras (most of the EOS series) use E-TTL, and the very latest Canon cameras (EOS 1D Mark II, EOS 1D Mark III, etc) use E-TTL II, and all three of these flash modes (A-TTL, E-TTL, and E-TTL II) also use a pre-flash. In other words, you are not going to get away from pre-flash by simply switching from P-TTL on Pentax cameras to either a Nikon or Canon.
stewart