[photo-3d] Re: To math or not to math?

[zilch0@xxxxxxxxxxxx]

Hi!

It looks like I'm the new "math maven" poster child.  I'll honor your 
opinions by providing additional material at which to chortle as I 
answer your comments.

--- In photo-3d@xxxx, "John A. Rupkalvis" <stereoscope@xxxx> wrote:
> 
> ----- Original Message -----
> From: "Dr. George A. Themelis" <drt-3d@xxxx>
> To: <photo-3d@xxxx>
> Sent: Wednesday, February 28, 2001 4:26 AM
> Subject: [photo-3d] To math or not to math?
> 
> > John, the thick photo books have been replaced by advanced
> > calculators.... Sorry, I cannot resist but quote this message
> > that came from the MF list (MF stands for Medium Format, not
> > Mathematical Formulas!!!)  I did not write this!!!  Email Paul
> > Talbot if you would like to join the MF stereo list.
> >
> > Here is the quote.... enjoy!!!!  -- George Themelis
> >
> > excerpt from:
> > http://www.pauck.de/archive/mailinglist/mf3d/mhonarc/msg04004.html
> 
> The description referred to above (which I removed, Paul!) is great. 
 It
> should be framed and hung on the wall in every stereo club.  I 
wonder if the
> writer has ever done stereo photography of birds or airplanes or 
sports, and
> if the subject was still around by the time that the calculations 
were
> completed (even with an advanced calculator)!

When time is short, I compromise.  When time permits, I avoid 
compromise.  Surely, most photographers enjoy some measure of 
increased deliberation when working with static subjects.  That which 
you find remarkable, even laughable, in my technique is the fervor 
with which I'm willing to pursue precision.  The article George 
referenced details the accuracy I permit myself with subjects like the 
hangared B17.  Your suggestion that I might be caught fumbling with 
the calculator at the expense of lost opportunity with animated 
subjects must be dismissed as facetious.  I enjoy precision when I can 
afford it. 
 
> The point that I like to make with the math mavens, is that: 1.) 
> usually it
> is not necessary, and 2.) it can actually be misleading and
> counterproductive.

The math is as necessary as your desire to extract performance from 
your film and equipment.  If a fellow is content with the results had 
using a fully automatic camera, his decision to do so should be 
respected and supported by others.  It's possible any greater 
attention to the science of photography would only compromise his 
capacity to express himself artistically, even when he's working with 
a static subject and has all the time in the world.  It's also 
possible that he simply lacks the knowledge and experience needed to 
control variables his equipment makes available to him.  It's possible 
he has struck a balance between the results he expects and the energy 
and patience he's willing to invest.   

Whatever the limiting factors are, if his expectations are being met, 
no one should find fault with the choices he makes.  If his says his 
expectations are not being met, we should lend a hand in teaching him 
how to tie down the lose ends.

If, at the opposite extreme, someone choses to identify and optimize 
every variable within his control, displacing ingornace with 
knowledge,  impatience with resolve, disinterest with enthusiasm, a 
sparsely provisioned tool box with every appliance that can extend an 
advantage, that decision should be respected as a matter of choice, 
equally worthy of support.

The closer one fits this latter extreme, the more valuable and 
necessary the math becomes.  The closer one fits the first extreme, 
the more "misleading and counterproductive" the math will be.
 

> I have shelves full of books on stereo photography written all the 
way from
> the late 1800's to the present time.   Many of these, possibly most, 
have
> tables in them purportedly showing where to set convergence for 
different
> focal length lenses (or in some cases, a specific focal length 
lens).  The
> interesting thing is that I have yet to find two books where the 
tables are
> identical!
> 
> So which one is right?  They all are.  If you take any particular 
setting,
> it is possible to find a subject (and viewing condition) for which 
that
> setting works.  The problem with assigning numbers to these things 
is that
> stereo photography is very subjective.  What works beautifully for 
one
> subject at one distance with one foreground distance and one 
background
> distance, may not work at all for another with identical distances. 
 How do
> you come up with a mathematical formula that takes into 
consideration ALL of
> the variables: color, texture, subject size, homogenous patterns, 
geometric
> patterns, strong vertical lines, intermingled depth cues (or lack of 
them),
> subject motion (and how fast in what direction), etc., etc.???
>

Your argument suggests that a mathematical approach excludes 
subjective input and permits no adaptability to circumstance.  In 
reality, such conclusions only exhibit a failure to understand which 
variables empower the control you believe is absent.  Depth of field 
and base separation formulas, for example, are often viewed as rigid 
and limiting only because constants are often used in place of 
variables.  

I can find countless examples of depth of field calculators which 
document their use of the constant 0.03 mm as the maximum permissible 
circle of confusion diameter for 35mm format.  The authors of these 
DoF utilities, be they spreadsheets, Palm programs, web-served java 
scripts or whatever, rob us of our one opportunity to influence the 
depth of field calculations to suit our personal preferences. 
Ignorance of how to exploit this variable abounds.

Similarly, a base separation formula like the 1/30th rule (Near 
point/30) offers no provision for adapatation or personalization other 
than our freedom to embrace the formula or reject it entirely in 
deference some other means for determining base separation.  Even 
formulas that offer variables of control on a silver platter go 
misunderstood and underutilized.  

The deviation variable in the formula used by John Bercovitz is a 
classic example.  Lots of people have failed to recognize that right 
there, in that singular expression named "d", you can infuse 
subjectivity to your heart's content.  The math perfectly fits the 
geometry of the medium, yet still provides a variable that's wide open 
to your tastes and even your experience with subjects of different 
"color, texture, subject size, homogenous patterns, geometric 
patterns, strong vertical lines, intermingled depth cues (or lack of 
them), subject motion (and how fast in what direction), etc., etc.???" 

Our thinking can be less flexible than the math.

> Better to go out and start shooting pictures.  Learn from 
> experience.

And then apply that experience with meticulous craftmanship or 
indifferent abandon.  It's entirely your choice to go to either 
extreme or somewhere in between, but we shall eat the fruit of our 
doings.

Mike



 

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