Someone with better knowledge than I may care to comment, but the movement
of the aperture indexing lever to greater than constant aperture should be
regarded by the body as overtravel rather than a change in the index value.
Does the index lever turn further clockwise (looking at the back face of the
lens) on a variable max lens than on a constant aperture lens?
Julian
----- Original Message -----
From: "Julian Davies" <julian_davies@xxxxxxxxxxxxxx>
To: <olympus@xxxxxxxxxx>
Sent: Sunday, January 16, 2005 11:54 AM
Subject: [OM] Re: Zuiko 35-105 question
>
> I think Simon's point is that the camera body doesn't know the
> relationship
> between the maximum aperture and the indexed aperture since the maximum is
> variable and the indexed isn't.
>
> The answer is to meter using the constant aperture dot, since this limits
> the maximum aperture and sets the relationship to the next smaller
> aperture
> as a constant. The lens will then actually behave as a constant max
> aperture
> lens, ie the aperture closes down all on its own as you zoom out,
> independently of the stop down lever. On the 35-70 there is a noticeable
> dimming of the viewfinder as you move from max to constant aperture at the
> 35mm setting, but of course no further dimming as you stop down further
> unless you push the DOF preview.
> Metering at max aperture will caused the error Simon describes. Of course
> in
> OTF auto, this is all academic.
>
> Julian
> ----- Original Message -----
> From: "Piers Hemy" <piers@xxxxxxxx>
> To: <olympus@xxxxxxxxxx>
> Sent: Sunday, January 16, 2005 10:32 AM
> Subject: [OM] Re: Zuiko 35-105 question
>
>
>>
>> No, it doesn't need to know the f/stop. It needs to know:
>> 1 How much light is cominh through the lens at fully open aperture;
>> and
>> 2 By how many f/stops the lens is stopped down below its fully open
>> aperture.
>>
>> It therefore doesn't matter to the camera metering system whether the
>> lens
>> is a 500/8 or a 50/1.2 and thus the position of the aperture reporting
>> lever
>> is simply the lens' actual aperture setting relative to fully open
>> aperture
>> - it does not report that "this lens is currently set at f/11". Take a
>> look
>> at a 500/8, compare it with a 50/1.2 and you will see what I mean.
>>
>> --
>> Piers
>>
>> -----Original Message-----
>> From: olympus-owner@xxxxxxxxxx [mailto:olympus-owner@xxxxxxxxxx] On
>> Behalf
>> Of Simon Worby
>> Sent: 16 January 2005 08:43
>> To: olympus@xxxxxxxxxx
>> Subject: [OM] Re: Zuiko 35-105 question
>>
>>
>> ---snip
>> Since the camera needs to know what f-stop is selected to give correct
>> and
>> accurate light meter readings, how does it know (or doesn't it?) on the
>> earlier model when the aperture lever should in fact be somewhere between
>> 3.5 and 4.5 (i.e. at anywhere longer than 35mm), but isn't? Or are the
>> light
>> meter readings just up to about 1/2 stop out?
>>
>> --snip
>>
>>
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>
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