Originally posted by bdery There is none that does exactly that. PTTL on wireless triggers is almost non-existant, the only roundabout solution is a company (I forget the name) which makes a device detecting the light bursts from the master wireless flash on your camera, and an emitter which does the reverse to the receiving flash.
That's Radiopopper's first PX version (their current one doesn't do that).
And yes, there are no PTTL wireless triggers.
If you really want to learn lighting, you'd get off the TTL crutch anyways. TTL is really only useful for events. Get a light meter and understand lighting ratios. Get a studio strobe and use the modeling lamps to position things.