Archived posting to the Leica Users Group, 2014/02/21

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Subject: [Leica] OT - Sony Alpha 7R
From: red735i at (Frank Filippone)
Date: Fri, 21 Feb 2014 21:56:07 -0800
References: <> <024c01cf2f90$3bfa4fd0$b3eeef70$> <>

You would need a reference calibration somewhere...and to be honest, the
camera does NOT know what is actually in focus and what is not.... it only
knows what should be in focus.... it is an open loop system....

Would you like to sit there at every F stop (and FL for a zoom) and
calibrate the focus shift for every combination?

This is a factory calibration, not a user calibration

Frank Filippone
Red735i at

-----Original Message-----
From: at
[ at] On Behalf Of 
Sent: Friday, February 21, 2014 9:49 PM
To: Leica Users Group
Subject: Re: [Leica] OT - Sony Alpha 7R

Couldn't the camera calibrate the lens? After all, it is an optical
computer; what is one more task added? 

Sent from my iPhone

Sonny Carter

> On Feb 21, 2014, at 11:37 PM, "Frank Filippone" <red735i at>
> That would require calibration of each lens ( maybe they all act the 
> same????)...
> I would think of this as a really good idea, but I also thought a R10 
> was a really good idea......
> Frank Filippone
> Red735i at
> Frank Filippone wrote:
>> If you are focusing at working aperture, what advantage is there to 
>> native lenses?
>> I'm not so sure Sony has this thought out......
> For those who are interested in such things, native-mount lenses will 
> allow shutter-priority and program exposure modes, and AF.
> Another way to handle focus shift would be to program the lens to tell 
> the camera how much shift there is at various apertures.  Given this 
> would be a native-mount lens the camera would know what aperture the 
> lens will be using.
> Doug Herr
> Birdman of Sacramento
> _______________________________________________
> Leica Users Group.
> See for more information

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Replies: Reply from sonc.hegr at (Sonny Carter) ([Leica] OT - Sony Alpha 7R)
In reply to: Message from wildlightphoto at (Doug Herr) ([Leica] OT - Sony Alpha 7R)
Message from red735i at (Frank Filippone) ([Leica] OT - Sony Alpha 7R)
Message from sonc.hegr at (Sonny Carter) ([Leica] OT - Sony Alpha 7R)