Archived posting to the Leica Users Group, 2010/04/14
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]I'd think extreme retrofocus designs to achieve maximum perpendicularity. Regards, George Lottermoser george at imagist.com http://www.imagist.com http://www.imagist.com/blog http://www.linkedin.com/in/imagist On Apr 14, 2010, at 4:48 PM, Jeffery Smith wrote: > I don't really recall Olympus's exact wording. I think the only way > to get perpendicular light rays to hit would be to have a very > large diameter rear element, and still they would not be actually > perpendicular, but maybe more perpendicular. > > > > On Apr 14, 2010, at 4:22 PM, Henning Wulff wrote: > >> The vignetting of the 45-200 is due to the attempt by Panasonic to >> keep the lens as small as possible, so vignetting appears at wider >> apertures due to cutoff of off-axis rays. If the vignetting were >> due to light rays hitting the sensor at a too steep angle, the >> aperture wouldn't make a difference. Also the latter is an issue >> with shorter lenses where the rear exit pupil is too close to the >> sensor. Not an issue with the 45-200. >> >> As I mentioned before, the vignetting doesn't bother me since the >> lens is only for digital use, and the software that I use >> certainly has no problems fixing the vignetting if so desire. >> >> BTW, that Olympus claim is not true; I'm not sure they actually >> said that. Their lenses are 'more telecentric' than those of most >> other manufacturers; true telecentricity causes so many problems >> that it's really not worth it except for certain industrial uses. >> >> >> >>> Is the vignetting due to the light rays hitting it at less than a >>> perpendicular angle? One of Olympus's big selling points on their >>> lenses is that the light path is exactly parallel to the APS- >>> sized sensor behind the lens. >>> >>> Jeffery >>> >>> >>> On Apr 14, 2010, at 3:05 PM, David Rodgers wrote: >>> >>>> I don't doubt what you're saying. I'm just a bit mystified how a >>>> lens >>>> can vignette on a sensor that's half the size of film that it was >>>> designed to cover. That hasn't been my experience with M lenses >>>> on Micro >>>> Four Thirds. I actually have to use Lightroom to add a little >>>> forced >>>> vignetting because in many cases I like that look. >>>> >>>> I'm also perplexed at how Contax G lenses can be materially >>>> better on >>>> Micro Four Thirds than are Leica M lenses, or even CV lenses for >>>> that >>>> matter. While I haven't used all on Micro Four Thirds I have >>>> used them >>>> all on film and for the most part they're all pretty good. Thus I'm >>>> curious as to why the performance would be so different on Micro >>>> Four >>>> Thirds. What kind of adapters are you using? >>>> >>>> The main issues I see in using Lumix lenses versus Leica M >>>> lenses on the >>>> GF-1 is that Lumix lenses have AF and Leica M lenses don't. It's >>>> easy to >>>> miss focus, particularly with the longer lenses wide open. A focus >>>> assist LED in the viewfinder would be a nice feature to have. >>>> >>>> Dave R >>>> >>>> >>>> -----Original Message----- >>>> From: lug-bounces+drodgers=casefarms.com at leica-users.org >>>> [mailto:lug-bounces+drodgers=casefarms.com at leica-users.org] On >>>> Behalf Of >>>> Simon Ogilvie >>>> Sent: Wednesday, April 14, 2010 3:03 PM >>>> To: lug at leica-users.org >>>> Subject: Re: [Leica] M Lenses on GF-1 >>>> >>>> I've used a variety of Leica and Voigtlander M lenses on a G1, and >>>> also a couple of Contax G lenses (45/2 and 90/2.8). Without >>>> exception >>>> I found the M lenses disappointing with either smearing, >>>> vignetting or >>>> other faults. The Contax G lenses however are superb on the >>>> micro 4/3 >>>> format and I much prefer the 90 to the 90 Summicron and the 45 >>>> to my >>>> (now sold) 50 Summilux. >>>> >>>> I've also been a bit disappointed with the performance of the >>>> Panasonic 45-200. I haven't checked but it's possible most of the >>>> shots I've taken have been at or close to full aperture, so the >>>> vignetting at the long end is very noticeable. It also doesn't >>>> appear >>>> very sharp at the long end either. Maybe the upcoming 100-300 >>>> will be >>>> better - I hope so. >>>> >>>> _______________________________________________ >>>> 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 >> >> -- >> >> * Henning J. Wulff >> /|\ Wulff Photography & Design >> /###\ mailto:henningw at archiphoto.com >> |[ ]| http://www.archiphoto.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