Ok, Robby boy, we have a building with an intricate antenna structure atop
the mechanical penthouse near my house. Using some of my favorite B&W, I'll
shoot it vertical frame with the shift at max extension, vertical film plane
(proper correction), and with the camera placed such that the antenna
structure is at the very top of the frame. I'll then set the lens for zero
correction and tilt the camera up to get, as best as possible, the same
view. I'll then have the local pro shop process and digitize the images
(from my experience, this will be about a 30 mb raw file). After correcting
the distorted image in PhotoShop. I'll crop to the antenna structure.
Perhaps, you're right and I'll see little if any difference in the rendering
of the structure's intricate vertical elements. Ya think?
Regards,
Bob...
From: "Rob Studdert" <[EMAIL PROTECTED]>
On 8 Mar 2005 at 15:16, Bob Blakely wrote:
Ah, the "digital age" crap again. The world is full of folks who think
they can
get something for nothing.
When you use Photoshop or other software to correct perspective because
you
didn't shoot the shot correctly in the first place, one of two things
will
happen...
either:
the photograph must be "stretched" to perform the correction
necessitating the synthesis of pixels (information) not in the original
shot, leading to a photo where some scene details are (essentially) the
computer's best guess.
or:
the photograph must be "compressed" to perform the correction
necessitating the loss of pixels (information) that were in the original
shot, leading to a photo where some scene details are (essentially) lost.
A shift lens eliminates both of these conditions by performing the
correction as a mater of photographic geometry when the image is formed.
This has got to be at least the tenth time this subject has come up in
the last
several years.
And you still don't get it? The loss (ie compression/stretch) is but a
very
small percentage in most but extreme cases of correction that no 35mm PC
lens
could achieve anyhow. I've made digital corrections to quite a number of
images
over the last few years and none have exhibited visible image degradation.
Also
you will find that any image must be equally compressed and stretched in
order
to preserve the aspect ratio when digitally correcting distortion.
Pentax have a grand total of one expensive (and on the *ist D pretty much
useless) shift lens, I sold mine some years ago and I haven't regretted it
for
a minute. The "digital age" crap simply lets me fulfil my photographic
visions
better than the tools available in the "golden days" of film. Cheer up
Bob.
