P3D Re: 3D realism and focus cues

[Dylan The Hippy Wabbit <spacey@xxxxxxxxxxxxx>]

Hi All,

Right now I've caught up with all the weekend's discussion I'll have my
tuppenny worth.

Phil Palmer asked about real-time focus adjustment in the viewer.  If you
could be sure of doing it fast enough it would probably be close to ideal,
simply because that is how the eye/brain works.  The whole world looks
sharp because the eye flits around the scene rapidly refocussing as it
goes.  I suspect that knowledge of this inspired Phil's original question.

As for whether this would fix cardboarding, well I'm not convinced.  The
consensus I've seen on this list seems to be that low image resolution is
the main cause.  By reducing the stereoscopic cues within an object this
causes it to look flatter.

I've a strong suspicion that there are psychological causes in addition.
A short digression will help explain why.  A study I read of many years
ago involved showing subjects playing cards in the wrong colours.  Spades
and clubs were red, and hearts and diamonds were black.  It could take a
surprisingly long time to recognise this.  Expectation would over-ride
what was there, or else the subjects would compromise and report them all
as purple.

So after a lifetime of seeing flat photos and drawings which looked just
that, it could easily be that cardboarding is an attempt to reconcile
seeing depth in a flat picture.  Showing my lenticular prints around I get
a lot of comments that, "It's doing my eyes in!"

My experiences fit that pretty well.  My introduction to 3D photos was
Serge Nazareiff's 'Stereo Nudes.'  When I first saw the illustrations
through a viewer I got just that cardboard look.  Then I began to notice
corners, slanting surfaces, arms and legs projecting towards the camera
and so on.  Now I can see full form in most of the pairs.  Only the very
flat lit (over here they call it page 3 lighting, after the tabloids'
usual site for a glamour shot) pairs still show little form.

Beyond these anecdotes I don't know of any evidence for this hypothesis,
but I like it.

Dave Spacey

______________________________________________________________________________

Walk tall, walk straight,
Spit the world right in the eye.

-Kevin Godley and Lol Creme


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