Well that's impressive. I've got to look into lightroom. Regards, Bob S.
On 11/7/07, Godfrey DiGiorgi <[EMAIL PROTECTED]> wrote: > BTW, in Lightroom, setting a lens vignetting preset to +55 on amount > and 14 on midpoint completely eliminates the falloff. > > see: <http://homepage.mac.com/godders/DAstar_50-135-falloff- > correction.jpg> > > Godfrey > > > On Nov 7, 2007, at 2:36 PM, Godfrey DiGiorgi wrote: > > > Photoshop shows values based on [EMAIL PROTECTED] 127 is the mid > > point, and it's about 25.5 points per EV step for the full range > > from Zone 1 to Zone 10. So 130 is right around Zone V and 80 is > > right around the boundary between Zone 3-4, so it looks like you > > are showing about 1.5-2 steps light falloff from center to edge > > wide open, a rough first order approximation. > > > > (Lightroom shows it to be about 51% brightness on center and 32% at > > corners, again showing a little less than 2 steps falloff to the > > corners. 10% on grayscale value is 1 step in Lightroom's scale.) > > > > Godfrey > > > > On Nov 7, 2007, at 1:53 PM, Dario Bonazza wrote: > > > >> Hi folks, > >> > >> Here is a white-wall shot taken with the DA* 50-135 @ 135mm F2.8, > >> where it > >> shows its highest light falloff at corners: > >> www.dariobonazza.com/public/Vignetting.jpg > >> > >> Do yo have any idea about how to measure that? I mean, how to > >> translate > >> Photoshop values (around 130 for each RGB channel at center, > >> around 80 at > >> corners) into f/stops? > >> > >> Thanks to anybody enlightening me ;-) > > > > > -- > 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. > -- 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.
