Teach me, please, Confusing about TTL and iTTL??
Teach me, please, Confusing about TTL and iTTL??(6 posts) (5 voices)
iTTL: Camera will determine flash exposure through iTTL pre-flashes, however Advanced Wireless Lighting is not supported. (from Nikon web-site)
TTL just mean through-the-lens.
Advanced Wireless Lighting is actually part of Nikon CLS technology developed so that iTTL could be used for multiply flashes...
Where did you find that information?
TTL vs. iTTL.
As I understand it, they are largely the same thing. Aparently TTL worked great on film, but really crappy for digital. Back in the film days, the light meter could read the reflections off the film and get the correct exposure. Digital sensors don't have the same reflective properties that film do, and they don't produce a very accurate reading for the meter.
To get around this, Nikon created iTTL. iTTL would use pre-flashes that reflected off the mirror before it was raised. This was a much better solution for digital. The only downside is that some people have a really overactive blink reflex, and will blink between the pre-flash and the actual exposure. Its really hard to shoot these people (about 1 in 20 based on my observation) using iTTL. Your better off setting your flash manually.
You can see a longer discussion about the difference here:
What Willis said
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