Contrast-Detect Auto-Focus, the method used on many P&S digital cameras and in Live View on some DSLR's to AF. It's very accurate but generally slower than the traditional AF units on DSLR's which can't be used when the mirror is up. It works by measuring contrast off the sensor.
-Adam On Sat, Sep 13, 2008 at 6:21 PM, David J Brooks <[EMAIL PROTECTED]> wrote: > CDAF.?? > > Dace > > On Sat, Sep 13, 2008 at 5:17 PM, Adam Maas <[EMAIL PROTECTED]> wrote: >> When everybody elses lensed designed "years" before Live View and CDAF >> work just fine? Yup. Canon and Nikon had much more significant hurdles >> to get 20 year old lenses to AF with CDAF than Oly did with at most 5 >> year old lenses designed for a focus-by-wire application like CDAF. >> Nikon, with it's obsolete screwdriver-drive AF pulled it off, and both >> Nikon and Canon have achieved it on lens-motor based lenses, despite >> their specs dating back to ancient times (the Nikon lens-motor control >> spec dates to 1983, the Canon to 1987). Wasn't 4/3rds supposed to be >> the 'modern, future-proof' mount? >> >> I don't expect the same level of AF speed from the older lenses as the >> new ones designed for the application, but the bloody things should be >> able to AF in the first place. Especially since Olympus designed them >> to be firmware-upgradable. Frankly I doubt this is even an engineering >> issue per se. More likely it's just a budgeting issue and they didn't >> spend the money to implement the necessary support either in the >> bodies or via firmware upgrades. >> >> Heck, despite all that I'm still enthused for the G1 and am seriously >> considering buying one once the 20/1.7 becomes available. >> >> -Adam >> >> On Sat, Sep 13, 2008 at 3:46 PM, Godfrey DiGiorgi <[EMAIL PROTECTED]> wrote: >>> Oh give it up. You want to say someone bungled something in lenses >>> designed *years* before the Live View and CDAF existed because it >>> makes you feel like you know something that their engineering people >>> dont and want to complain about it? fine, go ahead. >>> >>> Knowing how much hard work had to go into this design to make it do >>> what it does, I find it perfectly reasonable even with the feature >>> limitations. I'd rather have a lens that focuses manually very >>> accurately and conveniently than a lens that almost works well with an >>> auto focus system that it wasn't designed for. >>> >>> G >>> >>> >>> On Sep 13, 2008, at 12:34 PM, Adam Maas wrote: >>> >>>> Sony doesn't even offer CDAF on their SLR's, they use second-sensor LV >>>> and leave the mirror down to do phase-detection AF. Works very well, >>>> especially since they offer the fastest AF in-class already on the >>>> A300. >>>> >>>> If it's Panny pushing CDAF on 4/3rds and they didn't implement it in a >>>> way that would work with legacy lenses, it's their bungling, not >>>> Oly's. But it's still a bungle for 4/3rds. >>> >>> >>> >>> -- >>> PDML Pentax-Discuss Mail List >>> [email protected] >>> http://pdml.net/mailman/listinfo/pdml_pdml.net >>> to UNSUBSCRIBE from the PDML, please visit the link directly above and >>> follow the directions. >>> >> >> >> >> -- >> M. Adam Maas >> http://www.mawz.ca >> Explorations of the City Around Us. >> >> -- >> PDML Pentax-Discuss Mail List >> [email protected] >> http://pdml.net/mailman/listinfo/pdml_pdml.net >> to UNSUBSCRIBE from the PDML, please visit the link directly above and >> follow the directions. >> > > > > -- > Equine Photography > www.caughtinmotion.com > http://brooksinthecountry.blogspot.com/ > Ontario Canada > > -- > PDML Pentax-Discuss Mail List > [email protected] > http://pdml.net/mailman/listinfo/pdml_pdml.net > to UNSUBSCRIBE from the PDML, please visit the link directly above and follow > the directions. > -- M. Adam Maas http://www.mawz.ca Explorations of the City Around Us. -- PDML Pentax-Discuss Mail List [email protected] http://pdml.net/mailman/listinfo/pdml_pdml.net to UNSUBSCRIBE from the PDML, please visit the link directly above and follow the directions.
