[rollei_list] Re: Rolleinar 1 or Crop for Portraiture?
- From: Emmanuel Bigler <Emmanuel.Bigler@xxxxxxxx>
- To: rollei_list@xxxxxxxxxxxxx
- Date: Wed, 02 Nov 2011 15:54:47 +0100
Le 01/11/2011 21:57, Bob James a écrit :
I'm wondering about your experiences. For portraits can you get away
with using a Rolleinar 1 without too much distortion? Rolleinar 2?
Or do you prefer for closeups just to come in and crop? Thank you
Rollei-masters, Bob James
Well, in principle for a classical portrait, you should keep the
camera at a certain distance, whichever the focal length might be.
Say 1.5 metre, 5 feet or so. Hence a possible answer could be : Rollei
TLR, standard lens + crop.
The reason is that perspective rendition in photography, for most
lenses in actual use (telecentric lenses play in another league), does
not depend on the focal length but only on the distance between the
subject and the lens. Actually the part of the lens that counts for
measuring this "correct" distance for perspective rendition is the
entrance pupil of the lens; for a Rollei TLR the entrance pupil is
located not far from the iris blades. The actual position of the
entrance pupil inside the lens does not really matter in this
discussion.
The problem is that when you place the lens too close to the face of
your subject, you get a visible difference in magnification ratio
between the nose and the ears which was often considered (at least by
conservative people that, hopefully, you'll never meet on this
discussion group ;-) ;-) ) as being inaesthetic. The exception was the
case of good old images for the cover of vinyl records of rock-pop
music groups in the last century, where, on the contrary, a wide angle
lens in close-up was DEMANDED for group portraits ;-)
[digression]
However the rules have to be broken, so you could have a look at this
interesting (even if not convincing to me) series of portraits at 1:1
ratio with a 8x10" view camera,
http://trichromie.free.fr/trichromie/index.php?post/2010/02/20/Hug
fitted with a faithful Aero Ektar lens 178 mm (7") wide-open at f/2.5;
hence at 1:1 = 2f-2f position, the entrance pupil of the lens is
located at about 2x7 = 14" (356 mm) of the subject: what a scandal !!
But ! The depth of field is so shallow that you cannot see the nose
AND the ears sharp at the same time, hence the previous arguments
become totally irrelevant ;-) And at 1:1 the depth of field is also
totally independant from the focal length ... But here we are very far
from the Rollei TLR ...
[end of digression]
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