In a message dated 00-04-02 11:41:00 EDT, you write:
> Thanks for your suggestions. I have a "basic" question: what is TTL? How
> does
> it works? What's the problem if I buy a non-ttl flash?
>
> Thank you!
>
> François
>
"TTL" means "through the lens.," and this term can apply to either light
metering or flash metering. Pre-TTL was that long long ago time when we used
hand held meters. The meters then got mounted on the camera itself
(sometimes coupled with the shutter speed dial). A great advance was when
the meter was put in the camera so that it metered the light that went
through the lens (Pentax Spotmatic??).
Similarly flashes at first had no automatic mechanism to lower the flash
output from its maximum. A great advance was auto flash. A much better
advance was TTL flash, which monitored the intensity of the flash through the
lens (Olympus OM-2 was first here).
Ring flashes also come in three flavors, manual, auto and TTL. TTL is again
the best because it monitors the actual flash going through the lens.
The downside of ring flashes is that they tend to give flat, low contrast
lighting. This might be good for certain objects but gives an artificial
look to some nature photos. Also, if your subject is small in comparison to
the entire photo, the ring flash will overexpose the main subject.
Warren
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