Archived posting to the Leica Users Group, 2012/06/10
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]I finally got your data plotted on a log scale. http://gallery.leica-users.org/v/OldNick/image003+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 > >