Archived posting to the Leica Users Group, 2004/11/03

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Subject: Levelling: [was Re: [Leica] More snaps (Skopar)]
From: s.jessurun95 at chello.nl (animal)
Date: Wed Nov 3 11:37:40 2004
References: <r02010400-1035-60B9BD392DAE11D98C24000A957A8242@[67.86.119.182]> <p06100530bdaec2ed32cb@[10.0.1.2]>

I find that nearly all my pictures are tilted the same amount.
Today while looking in my barbers mirror i found that i tilt my head and 
neck slightly.
I postulate that is were the small tilt comes from.
best
simon jessurun
amsterdam


> That's an interesting number.  If I did the math right, it works out to 
> about  0.025 degrees.  So why is it so hard to level the camera with a 
> wide-angle lens?  I suspect the answer is in the "minification" and 
> restricted field of view of the usual finders. Visual size reduction plus 
> shorter baseline equals greater error. The finder brightlines, if it even 
> has them, might easily be off by a degree, too.  Without brightlines, 
> leveling is probably hopeless since your eye has no reference as to what 
> is square.
>
> Accurate reference lines in the finder are the only answer, as was 
> mentioned earlier this morning, but the the lines must be confirmed square 
> to the camera film gate, too.
>
> Photoshop is easier.  How did we ever live without it?
>
>
>
>
>>I had an interesting discussion with a cabinet maker and later with an
>>Intensive Care physician several years ago about the ability of our
>>"uncalibrated eyeballs" to discern "out-of-true" lines.  Cabinet makers,
>>I learned, have always known that the unaided human eye (assuming
>>average eyesight), can detect 1/64" and 1/128" over a length of 3'.  The
>>physician was treating my wife, who had a Swan-Ganz (sp?) catheter.  For
>>the treatment to work properly, as I recall, a long level had to
>>extended horizontally from the catheter entry site in her chest out to
>>the side of the patient.  Several nurses were fussing with the thing
>>when the doc came in and, rather impatiently explained to the nurses
>>that the human eye was more capable of detecting out-of-level conditions
>>than by using the level.  He then proceeded to demonstrate, and he was
>>right!
>>Amazing what the eye can do!
>>Ken Frazier
>>
>>_______________________________________________
>>Leica Users Group.
>>See http://leica-users.org/mailman/listinfo/lug for more information
>
>
> -- 
> Regards,
>
> Dick
> Boston MA
> _______________________________________________
> Leica Users Group.
> See http://leica-users.org/mailman/listinfo/lug for more information 


Replies: Reply from images at InfoAve.Net (Tina Manley) ([Leica] Re: Levelling)
In reply to: Message from kennybod at mac.com (Kenneth Frazier) ([Leica] More snaps (Skopar))
Message from r.s.taylor at comcast.net (Richard S. Taylor) (Levelling: [was Re: [Leica] More snaps (Skopar)])