Archived posting to the Leica Users Group, 2012/01/17
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]I use a Schneider 35XL with my medium format digital photography. Biogon design. I have eye-scars from the sharpness of this lens! Also have a center filter built for the lens. I still use a CornerFix type software which takes care of issues (lens cast) other than light falloff, as you say Mark. I'm considering trying CornerFix with this setup rather than the process I use (CaptureOne) so that I can work on everything (35mm and 4x5) in LR... Bob On Tue, Jan 17, 2012 at 9:21 AM, Mark Rabiner <mark at rabinergroup.com> wrote: > Did not mean to imply the filters would be better than this software. > I was just bringing it up. I know the issues involve more than just > lightening the corners which his all a filter could do. But color issues. > Fringing perhaps is the word. > > -- > Mark R. > http://gallery.leica-users.org/v/lugalrabs/winterdays/ > > > > From: Paul Roark <roark.paul at gmail.com> > > Reply-To: Leica Users Group <lug at leica-users.org> > > Date: Tue, 17 Jan 2012 08:46:06 -0800 > > To: Leica Users Group <lug at leica-users.org> > > Subject: Re: [Leica] Zeiss ZM 21 & CornerFix > > > > Mark Rabiner <mark at rabinergroup.com> wrote: > > ... > > Center filters is what > > symmetric glass are said to need and there's been a > > cottage industry making > > them for decades for all the finest lens > > manufacturers making symmetrical > > lenses notably the German ones Rodenstock > > and Schneider (JSK) for view > > cameras. > > All that I've seen so far are too large for the 21mm Biogon > > (46mm > filter size). Ideally, I agree that would be the best way to deal > with > > light fall-off, but in practice, I think I'll end up relying on > CornerFix and > > possibly multiple exposures. > > So far, the increased noise in the skies near > > the edges and corners > has been the main visible artifact. Increasing the ACR > > noise > reduction -- color and luminance -- in a second "development" of the > DNG > > has given me the smoothness needed to deal with the noise. (I > don't use any > > luminance and restrict even color noise reduction in the > main DNG conversion > > to avoid softening of details.) > > Paul > www.PaulRoark.com > > > > > > Though a modern > > retrofocal lens like the 21mm f2.8 Elmarit M ASPH is so well > > corrected after > > years of computer design that they almost emulate a true > > wide angle lens > > like a Biogon or SA. But I think almost not quite as far as > > correction goes > > say for architectural use a symmetric is the lens of choice. > > And its a shame > > the are monsters which weigh a ton comparatively. > > But gee there is no fall > > off an the edges. > > Me I'd buy a center filler which gave you fall off on the > > edges as I darken > > the edges on every image I ever make first in the darkroom > > and now digital. > > > > Sheet shooters love a Biogon or super Angulon with their > > amazing low profile > > compactness and don't mind the amazing lack of > > distortion at all. > > Witness the amazing history of SA use on Leica M. > > There > > have been more than a few shooters who shoot Leica M only for that > > reason. A > > few on the White House staff. With a nikon with a 105 on one > > shoulder and a > > Leica M4 with a 21 3.4 SA on the other. > > I've yet to score one I borrowed a > > modern Hassy superwide for a week and did > > lots of shooting with it. Much of > > it on a tripod with the camera carefully > > leveled. And at f11 with everything > > zone focused from 3 feet to infinity. > > I'll love it when I can work with a > > true wide again. As in own one. > > > > -- > > Mark R. > > > > http://gallery.leica-users.org/v/lugalrabs/winterdays/ > > > > > >> From: Paul Roark > > <roark.paul at gmail.com> > >> Reply-To: Leica Users Group <lug at leica-users.org> > >> > > Date: Sun, 15 Jan 2012 08:31:07 -0800 > >> To: Leica Users Group > > <lug at leica-users.org> > >> Subject: Re: [Leica] Zeiss ZM 21 & CornerFix > >> > >>>> > > LR apparently has a built in vignetting fixer in its later versions. > > Does > >>>> LR now negate the use of Cornerfix? > > > > > > It's possible that > > CornerFix is > >>>> superior to even Leica's lens-coding > > profiles. It is > > custom for each lens > >>>> and body. You could even make > > it custom for each > > aperture if you wanted. > >>>> Canned profiles may be > > less accurate for your > > particular setup. > > > > Actually, > >>>> the issue with the 21mm Biogon is that > > it's a symmetrical > > design -- said to > >>>> be terrible with the M9, with a > > nodal point that is > > way too close to the > >>>> sensor. But symmetrical > > designs are, in my view, > > superior in terms of > >>>> sharpness and distortion > > to retro-focus. The 21 > > Biogon is really sharp, > >>>> with no distortion. > > My 18mm Distagon, said > > by some reviewers to be the > >>>> best 18, is good, > > but not up to the > > Biogon. For making large prints, I was > >>>> a bit > > disappointed in the 18, > > thus the 21 Biogon experiment, which luckily > >>>> > > worked. But for > > ColorFix, I probably would have returned the Biogon as > >>>> > > unusable with > > the > >>>> M9. > > > > Paul > > www.PaulRoark.com > > > > > > _______________________________________________ > >>>> > > Leica Users Group. > > > > See http://leica-users.org/mailman/listinfo/lug for more > >>>> > > information > > > > > > > > _______________________________________________ > > Leica > > Users Group. > > See http://leica-users.org/mailman/listinfo/lug for more > > information > > _______________________________________________ > Leica Users > > Group. > See http://leica-users.org/mailman/listinfo/lug for more information > > > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information > -- Bob Adler Palo Alto, CA http://www.rgaphoto.com