Archived posting to the Leica Users Group, 2012/06/10
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Aram, I tried putting your table of data into Excel, and plotting it. When I saved it as a tiff file, the scales were stripped off. However, with shutter speed as the vertical scale, and f-stop as the horizontal scale, you can see the variations. There are definitely some spreads in the data, but it is hard to say whether it is just hardware variations or some sort of correction that is applied to the Nikon inputs. http://gallery.leica-users.org/v/OldNick/image001+copy.tif.html Jim Nichols Tullahoma, TN USA ----- Original Message ----- From: "Aram Langhans" <leica_r8 at hotmail.com> To: "Leica Users Group" <lug at leica-users.org> Sent: Sunday, June 10, 2012 11:00 AM Subject: Re: [Leica] Using M (and R) glass on a Sony NEX-7 Now DATA > That's what I mean, too, except the Nikon D7000 and D300 does not behave > the same as Howard's D700. > > Can anyone make sense of these data? > > Lens 1 is Nikon 50/1.2 > Lens 2 is Leica-R 50/2 Summicron > Lens 3a is Leica-r 35-70/4 shot at 35mm > Lens 3b is same lens shot at 50mm > Lens 3c is same lens shot at 70mm > > Subject, an evenly lit patch of grass in my front lawn. Went through the > f-stops twice for each lens to check consistency. Same reading each time. > > > f-stop Lens 1 Lens 2 Lens 3a Lens 3b > Lens 3c > 2 1600 1600 > 2.8 800 1000 > 4 400 400 640 500 > 640 > 5.6 200 100 160 200 > 320 > 8 100 40 50 60 > 100 > 11 50 25 30 30 > 50 > 16 25 15 20 20 > 20 > > As you can see, the Nikon behaves as it should be and meters correctly > through the f-stop range, halving the shutter speed for each smaller > f-stop. > The Leica lenses do not and progressively overexpose as you stop the lens > down. I am surprised that the zoom did not meter correctly wide open. In > my field experience, wide open is not a problem, and the overexposure only > starts to show up as you stop down. > > I am also surprised that the overexposure is limited to about one stop. > In my field experience I sometimes have to compensate about 2 stops. > > That said, there is about a one stop overexposure in this test while my > Canon, when I had it, would overexpose about 4 stops if you stopped down > enough. > > > > > -------------------------------------------------- > From: "H&E Cummer" <cummer at netvigator.com> > Sent: Sunday, June 10, 2012 6:04 AM > To: <lug at leica-users.org> > Subject: [Leica] Using M (and R) glass on a Sony NEX-7 > >> >> Date: Sat, 9 Jun 2012 16:13:38 -0600 >> From: Bill Nelsch <photobynelsch at gmail.com> >> Subject: Re: [Leica] Using M (and R) glass on a Sony NEX-7 >> To: Leica Users Group <lug at leica-users.org> >> >> I have a stupid question: When you say the D7000 is "linear" - what does >> that mean actually? How does that affect the exposure? >> >> Bill in Denver >> >> Hi Bill, >> By linear I mean that as you close down the lens aperture the shutter >> speed drops by an equal amount in terms of light transmission >> If you are at f5.6 and 1/500 and then close down to f8.0 the shutter >> speed adjusts to 1/250 - to f11.0 the shutter speed drops to 1/125 >> keeping the light transmission the same. That's what happens on the >> Nikon. On the Canon without Canon lenses that "talk" to the body >> as you close down a Leica R lens mounted with an adapter that isn't >> chipped the shutter speeds drift away from the above response and you get >> more and more exposure variation. >> Hope this clarifies my point for you. >> Cheers >> Howard >> >> >> > > _______________________________________________ > Leica Users Group. > See http://leica-users.org/mailman/listinfo/lug for more information > >