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

[jhnichols at lighttube.net (Jim Nichols)]

Aram,
I got the scales into the graph.  Maybe this will help.

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
>>
>>
>>
>
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