Re: [OM] Night exposures with OM-2SP - warning long message, but ON topic

[frieder . faig]

On Fri, Sep 22, 2000 at 08:10:47PM +1000, Wayne Harridge wrote:
> 
> Note:
> 
> 2. From f2 to f11 with OM-2N exposure times almost exactly double with
> aperture as expected.
> 
> 3. From f1.4 to f2 looks like the lens is not letting though 2x the light at
> f1.4 as at f2 !

This is a strange effect, but it is exact what the meter does.
>From F1.4 -> F1.2 the exposure indicator of my OM 2sp moves 1~1.5 Index fields
( 1/3~1/2-F-stop) instead of 3 for a hole F-stop.

This is caused due to the lever which is telling the camera how much the lens
is stopped down. The marks between F 1.4 and F 2.0 are nearer together than the
others which causes this difference. So it seems it is what the lens does.

This phenomen is visible on every Zuiko I have. The first F-stop is not a 
whole F-stop  ( at least one index missing). It is hard to guess why this is 
so and weather it affects the real speed of the lens?

Seems exposure with internal meter should always be correct,
but when working with a hand-held-meter? 

Frieder Faig

> results:
> 
> Aperture             OM-2SP              OM-2N
> 
> f1.4                      6 sec                    3 sec
> f2                         8 sec                    4 sec
> f2.8                      21 sec                  7 sec
> f4                         114 sec                14 sec
> f5.6                      128 sec                 28 sec
> f8                         128 sec                 55 sec
> f11                         -                         100 sec
> f16                         -                         183 sec
> 

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