Re: Advice needed on 180 APO with external meter

[imspl@pacific.net.sg (Tan Roland)]

Eric, Many thanks for your information. Just yesterday ,I shot some film on
the 180 APO. I could not use the TTL meter on the old Leicaflex SL because
it does not work. Using my handheld Lunasix, I notice that the E6 slides
were a little overexposed. I cant by how many f stops, but definitely over
exposed. I am going to burn some more film and keep all posted. Thanks. 

Roland

At 10:32 AM 28/05/96 -0700, you wrote:
>At 11:56 PM 5/28/96 +0800, you wrote:
>>Eric, regarding the 180 APO. I note your comments about the light
>>transmission. Does this meant that if I was using an external light meter, I
>>should under expose by say 1/3 stop because the 3.8 is really more like 2.8
>>? Comments would be appreciated.
>
>I would say you should test the lens (which is 3.4, not 3.8) and see what it
>does. A few frames will let you know. As for that matter, every lens you use
>needs to be tested like that for critical work. Why? Because no lens
>actually works at the given aperture. They have f-stops, which are the
>physical size of the aperture based on the focal length. Then there's the
>t-stop, which is the actual amount of light that passes through the lens
>after some of it has been diverted, because of the glass used, number of
>lens-to-air surfaces, coatings, etc.
>
>On the other hand, I never needed hand-held meters for anything except flah
>metering. I have always trusted, and been rewarded by the accuracy of
>Leica's selective metering. It takes some learning, and burning some film,
>but for those of us who don't pay for our film, that's not so bad. <g>
>(Within budgetary limits).
>
>For example, I used to shoot basketball with two lenses, mostly. A 90
>Summciron and a 180 Elmarit. In one particular gym (they all vary, of
>course) I would set the shutter speeds of the cameras at 1/500 for 6400 ISO.
>The 90 Summicron would be set at f3.5 and the 180 Elmarit would be set at
>f2.8. The exposure would be exactly the same on film. Why? Because the 90
>Summicron is more efficient with light than the 180 Elmarit. So test your
>lenses. If you can't tell the difference, then don't worry about it. If you
>can, you've gotten better control of the process. Let us know how it works
>out for you.
>
>==========================
>Eric Welch
>Grants Pass Daily Courier
>
>