E-TTL2 is the latest Canon Flash system, which uses pre-flashes and can
meter off-centre subjects (Which E-TTL 1 couldn't on digital bodies,
Canon's traditionally had issues metering off-centre subjects with EOS
cameras).
i-TTL is the latest Nikon flash system, which replaced D-TTL (DX flash
series) for digital and 3D TTL on the film bodies. It's also pre-flash
based on digital, and Pre-flash+TTL-OTF on the F6 film body (The only
non-digital i-TTL body). This is arguably the most advanced TTL flash
system on the amrket today.
P-TTL is the latest Pentax Flash system, available only on the DSLR's
and IIRC the *ist Film SLR (I'm not 100% sure which film bodies might
support P-TTL). Like i-TTL and E-TTL2, it's a pre-flash based TTL system
rather than TTL-OTF as per most TTL Flash metering prior to the Digital
Age. This is inherently less accurate than TTL-OTF, but only Fuji ever
got Off The Sensor flash metering to work (With the S2 Pro) and they
abandoned it as more trouble than it's worth.
-Adam
Shel Belinkoff wrote:
What do all those acronyms mean?
Shel
"You meet the nicest people with a Pentax"
[Original Message]
From: Adam Maas
E-TTL2 and i-TTL seem to be massive improvements over earlier systems.
P-TTL seems to be mostly that way, but it also seems to have issues with
the onboard flashes.
