Archived posting to the Leica Users Group, 2017/01/27
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Good advice in this thread. I've used the focusing method outlined in previous posts with Micro 4/3 cameras for years. As others say, it's slow, but it works. Here's a trick that might help when using fast lenses with focus shift on a mirrorless camera. If you are going to shoot stopped down, focus at f/2.8 instead of wide open. With sufficient magnification, at f/2.8 you can still see a point of best focus rather than a broad zone. And f/2.8 displays most or all of the focus shift. I've shot a test series at all stops on every RF lens I own. This tells me what to expect when I use it. It seems that for most fast f/1.2 - f/2 lenses, the most drastic shift occurs between f/2 and 2.8. The same principle works for rangefinder focusing, too. Remember how Zeiss will optimize their recent 50/1.5 Sonnar for either wide-open or f/2.8? Why? Because if optimized for 2.8, the smaller stops fall pretty much into line. My non-FLE 35/1.4 Summilux ASPH also has focus shift. Wide open and at f/2, the rangefinder is accurate. At f/2.8-5.6, it focuses a little behind where the RF says. So I need to lean back slightly or focus a tiny bit closer. By f/8, DOF compensates, and I don't need to worry about it. The above applies to shots where we only care that the subject is in focus, and not if the zone extends a little in front of or behind the subject. If the exact placement of the focus zone is important, then use your focus magnifier mode and carefully focus at shooting aperture. --Peter On Thu, 26 Jan 2017 "Frank Filippone" <red735i at verizon.net>wrote: >... >... >... >I should mention that even with a Digi-Leica camera body, focus shifting is >an issue. It is inherent in the specific lens design. There is no camera >body based fix possible. With a EVF, you have the ability to correct >it.... >Using more DOF ( smaller aperture) will help mask this error source. >Your other choice is to not use focus shifting lenses..... or suffer trying >to get really sharp focus on your subject by focusing initially at shooting >aperture, which will be frustrating, especially at F32 ( for example). >... >.. >... >Frank Filippone >Red735i at verizon.net <Red735i at verizon.net> ========================================================================================================================== A concern with f/32, or even f/16 on FF or smaller sensors is diffraction. I posted a picture of a toy elephant head and a Brannock Device this month. < http://gallery.leica-users.org/v/Alan+Magayne-Roshak/Miscellaneous/20170108_MR_Mine_DSF3901.jpg.html > When I was shooting it (on a 20 lb. tripod) I was trying to get everything in focus, but I had to settle for f/11. I could see a softening of detail on the focused point as I stopped down past f/8, especially at f/16 and f/32. The frame at f/11 was the best compromise between sharpness and D.o.F. FYI, the lens was a 35mm f/3.5 Perspective Control Nikkor. Ref: <http://hyperphysics.phy-astr.gsu.edu/hbase/phyopt/cirapp.html#c1> -- Alan