Archived posting to the Leica Users Group, 2013/01/06

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Subject: [Leica] IMG: Pt.Lobos Formations
From: red735i at verizon.net (Frank Filippone)
Date: Sun, 06 Jan 2013 15:05:23 -0800
References: <CAAsXt4Ou+dC10_6A2vVH0BcG0SKEgCTNL+3wU5K7X6sirhsi6g@mail.gmail.com> <CD0F3685.3090%mark@rabinergroup.com> <CAAsXt4OgVth5zZmwX2o+2jWODs4TTjy2ySmT2yU_M26rCUQ07A@mail.gmail.com> <045f01cdec5f$d2c1fff0$7845ffd0$@verizon.net> <CAF8hL-GTQ_CqEe6t2s9_UvFcPiuhkzWPFynOuspXP-h0M=i+hQ@mail.gmail.com>

Yes, I understand that... but where do you get shims that differ in
thickness by 1/100 of a mm and in the shape and with the holes required to
actually DO the calibration?

In Bob's case he would have had to buy 100++ shims to do this.... not really
practical as a DIY program.... Did Bob send it to the factory/;service
center for calibration?

Frank Filippone
Red735i at verizon.net

Pretty simple: add or remove shims, focus on infinity, download image and
examine at 100%, lather rinse and repeat. So you start with "thick" shims,
and adjust to using thinner ones toward the end...


On Sun, Jan 6, 2013 at 2:47 PM, Frank Filippone <red735i at verizon.net> 
wrote:

> That is fascinating.....!
>
> I always suspected it was not as easy as taking out of the box and 
> shooting.......
>
> So how did you get the shims?  And did you do the "calibration" yourself?
>
> Frank Filippone
> Red735i at verizon.net
>
> I found the GG not to be reliable on these technical cameras with 
> medium format backs. I had been using the ground glass, which, though 
> it looked sharp, often was not. These sensor are so remarkably flat 
> that even being off 1/100mm will cause out of focus images. That's why 
> Alpa allows users to shim the piece that holds the digital back onto 
> their cameras to be adjusted with shims by 1/100mm. Other digital 
> technical cameras allow you to adjust the focus point of each lens to 
> the back. The manufacturing tolerance of the back's mounting plates 
> are not within this range.
>
> The difference between my traded in back and this back was .1mm (the 
> back had to be positioned .1mm closer).
>
>
>
> _______________________________________________
> Leica Users Group.
> See http://leica-users.org/mailman/listinfo/lug for more information
>



--
// richard <http://www.richardmanphoto.com>

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In reply to: Message from rgacpa at gmail.com (Robert Adler) ([Leica] IMG: Pt.Lobos Formations)
Message from mark at rabinergroup.com (Mark Rabiner) ([Leica] IMG: Pt.Lobos Formations)
Message from rgacpa at gmail.com (Robert Adler) ([Leica] IMG: Pt.Lobos Formations)
Message from red735i at verizon.net (Frank Filippone) ([Leica] IMG: Pt.Lobos Formations)
Message from richard at richardmanphoto.com (Richard Man) ([Leica] IMG: Pt.Lobos Formations)