Originally posted by unkabin jogiba, thanks for that link.
Lowell, how would you characterize ttl's behavior compared to p-ttl?
Thanks for any (more) input.
I use flash for specific purposes, one way is in wildlife with telephoto lenses like the shot I posted in this thread.
For wild life I prefer TTL, I deliberately set the camera up in manual, run maximum shutter speed (1/150 on the *istD) and stop down 1-2 stops to underexpose 2-4 stops. This means TTL dominates and exposure is good. The other issue I have with P-TTL is the preflash used for metering can be a disturbing factor in wild life, causing some subjects to move
For other shots, especially fill flash, I think P-TTL does better, because it calculates the flash intensity needed based upon the unaided exposure and adds what is needed considering the fill exposure, natural plus fill flash. As a result, P-TTL is less likely to over expose in fill flash situations.
I actually think each flash control method has its place, but since having both TTL and P-TTL requires additional hardware, sensors, A-D channel for metering etc, it cost a lot more to run both schemes. The *istD was a very expensive camera and this is part of why.