You must then be talking in regard to autofocus cameras. My TTL flash experience is with an LX. Obviously, an LX doesn't take distance into account, nor would the TTL flash units that work with an LX. If I'm using TTL flash on a subject that doesn't fill frame and there is an obvious difference between it and the background, I don't get a perfect exposure without dialing in some compensation.
Brendan wrote: > Part of the debate is how does distance info play a > part, or if it > does. The reason for the whole question is lets say > you have an off > center subject that you focused on. Why is she ( the > girl with the > strapless dress ) correctly exposed when you have > foreground and > background ambient ETC ETC. > > --- Paul Stenquist <[EMAIL PROTECTED]> wrote: > > I've missed some of this, but I don't understand > > what the debate is about. All the > > TTL camera knows is how much light hits the senosr > > (or in the case of LX, the film > > plane). When there's enough for a proper exposure, > > the flash duration is terminated. > > The exposure will be correct as long as the flash's > > full output is sufficient for > > the stop and film speed you're using. > > Paul > > > > Bruce Dayton wrote: > > > > > William, > > > > > > The biggest flaw I see to Tom's observations is > > when you bounce or > > > diffuse the flash. How would the body go about > > knowing that is what > > > you are doing? In those cases, you should see > > severe underexposure. > > > My experience is that they work fine. > > > > > > Bruce Dayton > > > > > > Wednesday, March 13, 2002, 11:54:55 AM, you wrote: > > > > > > PWO> Bruce Dayton wrote: > > > >> I have often wondered what the metering pattern > > is for the TTL sensor > > > >> - I'm guessing it is center-weighted. That > > could also account for > > > >> some differences. > > > > > > PWO> Hi Bruce, > > > > > > PWO> I've wondered this same thing, and I'll bet > > you're right about the > > > PWO> center-weighted pattern. Somebody shot and > > posted links to a whole series > > > PWO> of TTL flash shots of some shiny metal object > > against a fairly neutral > > > PWO> background, a few months back. A bunch of > > different apertures, shutter > > > PWO> speeds, etc. Can't remember who it was -- I > > was thinking it was either you > > > PWO> or Doug Brewer, but I just can't remember. I > > remember the look of the > > > PWO> shots, though. As best as I can recall, > > those shots appeared as though the > > > PWO> TTL flash metering was center-weighted, or > > pretty darned close to > > > PWO> center-weighted. There were some overexposed > > shots at the fastest apertures > > > PWO> that were attributed to the flash not being > > able to quench in time. > > > > > > PWO> I guess the way to test Tom V's idea (about > > the possibility that the flash > > > PWO> intensity is calculated from distance and > > guide number information, but not > > > PWO> controlled by an actual TTL sensor reading) > > is to fire a test shot with and > > > PWO> without the lens cap in place. If the TTL > > sensor doesn't matter, then the > > > PWO> flash intensities for both of these test > > shots should be about the same, and > > > PWO> the recycle times should be about the same. > > If the sensor really ~is~ > > > PWO> metering and controlling flash output, then > > the lens-cap-in-place test shot > > > PWO> should have a ~much~ longer recycle time. > > > > > > PWO> Bill Peifer > > > PWO> Rochester, NY > > > PWO> - > > > PWO> This message is from the Pentax-Discuss Mail > > List. To unsubscribe, > > > PWO> go to http://www.pdml.net and follow the > > directions. Don't forget to > > > PWO> visit the Pentax Users' Gallery at > > http://pug.komkon.org . > > > - > > > This message is from the Pentax-Discuss Mail List. > > To unsubscribe, > > > go to http://www.pdml.net and follow the > > directions. Don't forget to > > > visit the Pentax Users' Gallery at > > http://pug.komkon.org . > > - > > This message is from the Pentax-Discuss Mail List. > > To unsubscribe, > > go to http://www.pdml.net and follow the directions. > > Don't forget to > > visit the Pentax Users' Gallery at > > http://pug.komkon.org . > > > > ______________________________________________________________________ > Find, Connect, Date! http://personals.yahoo.ca > - > This message is from the Pentax-Discuss Mail List. To unsubscribe, > go to http://www.pdml.net and follow the directions. Don't forget to > visit the Pentax Users' Gallery at http://pug.komkon.org . - This message is from the Pentax-Discuss Mail List. To unsubscribe, go to http://www.pdml.net and follow the directions. Don't forget to visit the Pentax Users' Gallery at http://pug.komkon.org .
