Igor Roshchin wrote: > Mon Aug 27 09:58:53 EDT 2007 > William Robb wrote: > > > >> ----- Original Message ----- >> >>> From: "David J Brooks" >>> >> Subject: Re: Wedding photography >> >> >> >>> I have proven to my self over an over, if i'm going to do indoor >>> flash, the SB80DX and D2H are the only way to go for me. More >>> consistant results. >>> >>> Sorry Pentax wedding folk.:-) >>> >> I've had no luck at all with Pentax's flash control over the years. From the >> LX and it's refusal to fire the flash in fill situations to the istD and >> it's really bad TTL control to the K10 and it's klunker flash interface, >> I've just never liked using pentax camera controlled flash. >> I think the people who are happy with it have never used a good flash >> control system such as Nikon's. >> >> > > I liked the combination of ZX-5n+AF500FTZ in TTL mode. > Not a perfect combination but good enough. > I never had that much experience with the automated flash control system > of Nikons. > > If my understanding of how the TTL metering works is correct, > I suspect that the DSLR introduced a new, almost "fundamental" > (although, probably technologically solvable) problem: > due to the highly reflective sensors, the measurement of the > much higher intensity reflection during the flash burst : > a) requires a higher dynamic range meter, and > b) depends more on the exact way the light bounces back from > the object and from the sensor, -I think they do some sort of > extrapolation in the electronics - to estimate when the flash > needs to be turned off. > Thus, TTL metering in DSLRs is less accurate. > That's why, I suppose, they have to come up with more complicated > ways, like P-TTL. > > I wonder though, why the metering is still done via reflection from > the sensor (is that the case?), Doesn't P-TTL use a "preflash" so that metering via the "usual" path (of normal exposure metering) may be used (because the shutter is not open and the mirror is not up)?
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