Archived posting to the Leica Users Group, 2012/06/10
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Why does all this matter? Look at the histogram and adjust! Digital makes it so easy to get a good exposure.... Cheers Jayanand On Mon, Jun 11, 2012 at 1:15 AM, Jim Nichols <jhnichols at lighttube.net>wrote: > Aram, > > I will add to the confusion. > > After plotting your data on the NEX-7, I became curious about my Olympus > E-1, which is an early professional model. I compared the companion lens, > which was the Olympus 14-54 zoom, to my Summicron-R and my Elmarit-R 60mm > Macro. By some stroke of luck, I was able to use a log scale for this one, > which helps with the comparison. I have tried to do the same for my first > chart of your data, but can't find that option again. > > If the 14-54 lens, which communicates with the camera, is taken as the > "standard", then my Elmarit-60 is not too far off this line. However, my > sample of the Summacron-R 50mm shows that it departs from the norm, > particularly above f/8. In your data, this departure starts at about > f/5.6. After seeing this, I would not choose the Summicron-R as a measure > of performance for a Leica prime lens. My Elmarit-R 60 looks much better. > > In looking at your data for the Leica zoom, I begin to wonder if there are > too many compromises in zoom lens design. I did not pursue recording the > 14-54 data at other focal lengths. > > 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<http://leica-users.org/mailman/listinfo/lug>for >> more information >> >> >> > > > ______________________________**_________________ > Leica Users Group. > See > http://leica-users.org/**mailman/listinfo/lug<http://leica-users.org/mailman/listinfo/lug>for > more information >