Archived posting to the Leica Users Group, 2010/08/22
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]And the main engineering solution to the near-far correction problem is a floating element, which Cosina is not set up to manufacture. I'd have preferred a design like the 35/1.2 with little focus shift but lower overall contrast. But I already have a 75 Summilux. Marty On Sat, Aug 21, 2010 at 6:47 AM, Henning Wulff <henningw at archiphoto.com> wrote: > It takes a rather large amount of effort and expense to get rid of > spherical > aberration, which is the main cause of focus shift. The problem is that if > you just try to use aspherics to get rid of spherical aberration at long > distances you are likely to get overcompensated spherical aberration at > some > distance and apertures, and that is one of the main causes for nasty bokeh. > > This lens is supposedly based on the old Heliar design from Voigtl?nder of > old; mainly the large format lens designs that were the classic portrait > lenses of their time. These had a 'glow' which was very appealing, and the > focus shift could be dealt with by re-checking the focus after stopping > down. It was never that serious, and since pixel peeping had not yet been > invented, often went unnoticed. > > > At 1:30 PM -0700 8/20/10, mehrdad wrote: >> >> tom a mentions about a glow wide open , which i translate to focus shift. >> all the latest cosina lenses have focus shift syndrome, i wonder why! and >> leica is getting away from it as fast as they can. >> On Fri, Aug 20, 2010 at 12:37 PM, Henning Wulff >> <henningw at archiphoto.com>wrote: >> >>> ?I had a chance to play a bit with Tom Abrahamsson's copy of the lens. It >>> ?looks very nice, and seems a bargain at the likely price of $7-800US. >>> It's >>> ?about halfway in size and weight between the 75/2 and 75/1.4 of Leica's. >>> The >>> ?hood is not built in, but can be reversed with a unique screw in/clamp >>> on >>> ?two part design that seems a bit fiddly. >>> >>> ?I didn't do any rigorous testing, but it seems more like the Summilux in >>> ?character and would make an excellent portrait lens, hence 'Heliar >>> Classic'. >>> ?It seems very sharp though at f/1.8 with very pleasing bokeh. It seems >>> to >>> ?have some focus shift, just like the Summilux, but it's very little. >>> ?Unfortunately, like the 75/2.5, it only focusses to .9m. >>> >>> >>> >>> >>> ?At 5:17 PM +1000 8/20/10, Geoff Hopkinson wrote: >>> >>>> ?For anyone interested a friend of mine is the local distributor for >>>> ?Voigtlander products and he has just released details of a new 75mm M >>>> ?mount >>>> ?lens in their range. You can read the detail on his blog here. >>>> >>>> ?http://mainlinephoto.wordpress.com/ >>>> >>>> ?Cheers >>>> ?Geoff >>>> >>> > -- > > ? * ? ? ? ? ? ?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 >