P3D Re: Richmond, and Base

[Project3D@xxxxxxx]

In a message dated 07/08/98 14:55:13 GMT, Bruce Springsteen  write:

<<  Michael Georgeoff said:
    A mouthful!
 
 His encyclopedic posting on the 31 flavors of base calculation rivals
 anything I've seen lately, even from the formidable Dr. T.  He knows
 the dangerous characters have all finished "meeting" in Richmond and
 are now just "pieces of gingham and calico".  So while the cats are
 away, Michael the Mouse didn't just play - he roared!  And he asks if
 I'm with him.
 
 I'll nibble this cheese in a small way and see if any of the big cats
 are really still around.>>

Do I count as a big cat? - I'm here, at Richmond, and NOT eating cheese!
 
<< Seems to me that (aside from the 1:30 rule) the Holy Grail of base
 calculation is to make darn sure you don't exceed an on-film deviation
 of 1.2 mm on 35 mm film - on-film deviation being the difference
 between the far-point separation and the near-point separation.  Most,
 if not all the systems I have taken the time to dig into seem to bow
 to that figure, with minor exceptions.  But I might be wrong. ;-)
 
 Andrea's question about where to measure from was on my mind too.  I
 only have a 35-70 zoom on my SLR and was foolishly measuring from the
 foremost lens to the near point on my main subject - 15 inches.  I
 took a series of shots in this, my first close-up tabletop attempt,
 beginning with the 1/2 inch (1/30th) base, then increasing 1/2 inch
 for each succeeding shot, perhaps up to 2.5 inches.  The pairs that
 finally pleased my eye were more like 1.5 to 2 inches base, FL on lens
 near 50, so I have no idea what happened.  Which I guess puts me for
 now in the "don't worry, shoot happy" class.  But it's an uneasy state.
 
 The only other thing I know is Andrea said in her preying mantis macro
 article in the PSA journal that she was shooting with no mathematical
 contemplation whatsoever, much to her husband's disgust.  The only
 samples of her results I have seen looked gorgeous, so ignorance may
 indeed be bliss, at least for the lucky.
 
 That's all I know about this so far.  And half of it is probably wrong. >>

Well, Andrea gave her interesting, and illuminating, talk yesterday. Her
method is certainly the one that I would advocate - suck it and see! However,
you need some experience of how things will look from previous experiments,
and it's here that you combine a intuitive assessment of the 1:30 rule to get
a sterting point, but one probably wouldn't do any calculations. With close-
ups, you can go to 1:15 without any real problems, but you sill have to limit
thew depth in the scenrs if the final result is lekely to be viewed
comfortably by projection...

Bob Aldridge


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