Archived posting to the Leica Users Group, 2005/05/17

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Subject: [Leica] PAW 20 Millenium Bridge and St. Paul's - Try this!!
From: douglas.sharp at gmx.de (Douglas Sharp)
Date: Tue May 17 15:46:56 2005
References: <4289F4EB.3090809@summaventures.com> <4289F66A.1080407@gmx.de> <428A64F5.2080904@summaventures.com>

Much better Peter,
I know I'm a nit-picker, shifts, be they ever so small, just hit me
right in the optic nerve.

It's a matter of "Seismogram Eyeball", I spent over 30 years having to 
recognise amplitude and phase differences of seismic signals and logs, 
or time shifts of around 1 millisecond on seismic profiles (at a 
standard display scale that's about 0.1mm differences or smaller).Not 
finding the signal could mean the difference between drilling on a dry 
prospect or finding a gas reservoir.
"Sharps Eyes" had quite a reputation in the world of exploration geophysics.

It has a nasty side effect - I turned into a habitual picture frame 
straightener,BTW my wife is an architect and has the same gift/problem.

I put a narrow grid over the picture to check how much I was out on my 
first estimate, and I came to 0.4 - 0.85 degrees left correction. 0.85 
at the left hand edge (the parapet and windows of the rectangular 
building), 0.5 over the ends of the handrails at each side of the shot, 
based on putting the spire of St Pauls as a vertical axis dead centre. 
0.4 - 0.5 also fits the columns of the dome. This could infer a tiny bit 
of lens distortion, that the camera was not quite in the horizontal 
plane, possibly tilted up a bit, or that the scanned negative was not 
quite flat.
cheers
Douglas

Peter Dzwig wrote:

> Douglas Sharp wrote:
> 
>> An excellent shot Peter,
>> love the symmetry!
>> but couldn't it take a slight correction of the horizontal?
>> I think its about 1 or 1.5 degrees out of kilter. Otherwise perfect 
>> for me.
>> cheers
>> Douglas
>>
> 
> Douglas and List,
> 
> see which one you you think is straight...
> 
> http://gallery.leica-users.org/album164/MilleniumBridge200505
> 
> the original
> 
> or:
> 
> http://gallery.leica-users.org/album164/MilleniumBridge200505Rot1
> 
> I think that it is it straightened...it took 0.4 degrees of rotation. If 
> that does truly fix it (I am not entirely sure) Douglas you have very 
> sharp eyes!!
> 
> All the best,
> 
> Peter
> 
> 
> _______________________________________________
> Leica Users Group.
> See http://leica-users.org/mailman/listinfo/lug for more information
> 
> 

Replies: Reply from lkhermann at bresnan.net (lkhermann) ([Leica] PAW 20 Millenium Bridge and St. Paul's - Try this!!)
Reply from pdzwig at summaventures.com (Peter Dzwig) ([Leica] PAW 20 Millenium Bridge and St. Paul's - Try this!!)
In reply to: Message from pdzwig at summaventures.com (Peter Dzwig) ([Leica] PAW 20 Millenium Bridge and St. Paul's)
Message from douglas.sharp at gmx.de (Douglas Sharp) ([Leica] PAW 20 Millenium Bridge and St. Paul's)
Message from pdzwig at summaventures.com (Peter Dzwig) ([Leica] PAW 20 Millenium Bridge and St. Paul's - Try this!!)