Archived posting to the Leica Users Group, 2015/11/15

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Subject: [Leica] The SL
From: hjwulff at (Henning Wulff)
Date: Sun, 15 Nov 2015 12:15:18 -0800
References: <> <014d01d116cb$0c9f6580$25de3080$>

I use various longer lenses at stopped down apertures with an EVF and find 
that I get excellent focussing accuracy at working aperture. I don't use 
focus peaking as that is generally not sensitive enough and just focus on 
the viewfinder image and sometimes, if I have time, on the magnified image. 
It usually isn't necessary, though. All on A7rII.

In any case, I don't find lack of auto aperture much of a deal, and gain the 
benefit of having a true representation of the resulting dof, which is much 
more useful as far as I'm concerned.

Lots of thing wrong with the Sony, but that's not one of them.

Henning Wulff
hjwulff at

On 2015-11-03, at 10:35 PM, Frank Filippone <red735i at> wrote:

> Yes, all true.....but you forget that DOF is, for example at F8, greater
> than at F2.  So focusing is much less precise without auto stop
> down..........
> Frank Filippone
> Red735i at
> Do I have it right that the desire for automatic diaphragm control is for
> focus at maximum aperture then stopping down to shooting aperture at the
> moment of exposure?
> Doesn't the use of the EVF potentially permit the finder brightness to be
> controlled? If the lens is stopped down (ie not operating with auto
> diaphragm) of cause the image arriving at the sensor is what is used for
> focussing. So the desire for auto diaphragm control comes from the OVF
> systems?
> M lenses of course are already being employed with the initial SL units in
> the field.
>> You can get autoexposure only if the camera knows what the open 
>> aperture and the taking aperture are. If the lens does not generate 
>> those info, then some kind of manual system is needed
> Autoexposure with TTL metering in apertured-preferred mode is simple with 
> no
> auto-diaphragm, no data other than light, ISO and shutter speed is needed.
> With TTL metering and an automatic diaphragm the camera needs to know the
> difference between open aperture and working aperture.  It does not need to
> know what the actual open aperture is or the actual working aperture, only
> the difference.  Any other data is extra and can be used for the user's
> convenience, but is not required for autoexposure function.
> _______________________________________________
> Leica Users Group.
> See for more information

In reply to: Message from hopsternew at (Geoff Hopkinson) ([Leica] The SL)
Message from red735i at (Frank Filippone) ([Leica] The SL)