[Leica] Using M (and R) glass on a Sony NEX-7 Now DATA

[leica_r8 at hotmail.com (Aram Langhans)]

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
>
>
>