Parallax and Polarization

Question

Thanks to Terri and Grant I have been following The Radiant Vista's wonderful Daily Critiques. The one for January 29 at
http://www.radiantvista.com/dailyCritique/index.php
speaks about parallax and polarization in this straight-on photo of a flat-fronted, Spanish style church at high noon. But the photo, as submitted, has a dark sky, which the critiquer attributes to use of polarization. Obviously this has to do with contrast. But, what does "polarization" mean exactly?
The critiquer then performs a very neat trick of correcting the minor parallax to the left and right. He is using Photoshop. Is there a way to do this in PSE 3 for Mac?
Gordon McGilvray

Answer 1

Gordon,
Yes, Trish is correct. He's referring to the photographer having used a
polarizing filter on the camera. If you want to read a bit more about
polarization, see
http://www.luminous-landscape.com/tutorials/polarizers.shtml
The fellow doing the critique frequently mixes up the terminology. In this
photo, for example, he says "parallax correction" when he should have said
"perspective correction". In another video, I heard him repeatedly say
"high key" when it was clear he meant "high contrast". I don't try to keep
track of the flubs. It's generally clear what he means through his actions,
don't let the terminology flubs confuse you.
Now for your question about "Perspective correction" in Elements. Yes, you
can do it. Elements has several Transform options. The two most useful
for perspective correction are the "Perspective" transform and the "Distort"
transform. You could probably use "skew" also but my personal preference
would be to use distort rather than skew. Feel free to use what feels right
to you.
The Perspective transform is intended to make perspective corrections easy
to do. You get eight transform handles (the little squares on the bounding
box) -- one at each corner and one in the middle of each side. Drag the
side handles, and the image skews. Drag a corner handle and the opposite
sides tilt in or out depending on the direction of drag. If the shot is
relative simple, this transform will do what's needed with a little
practice. I find it easier to use if I zoom down the image size and leave
the gray matte area to show the changes in the bounding box.
The distort transform is trickier to use but more flexible. Sometimes, I
find that a different correction is needed on each side (more than one
principle plane usually). In this case, the perspective transform won't
quite work as it makes the same adjustment on each side. But, using
Distort, I can adjust each corner independently and, by one at a time top to
bottom, and left to right, get the lines to straighten out and be parallel.
It's a little tricky as one adjustment can affect the others, but a little
rework and you can home in on the desired result. When you get used to it,
it's pretty quick and easy.
One note: If you are working with only a background layer, you have to
convert it to a regular layer to use the transform tools.
Have fun,
Bob