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How Shift Lenses Change your Life
Instead, a one-piece TS-E 35mm F/2.8 or 3.5 lens should have much better optical quality (no TC), as
well as being cheaper (no TC), lighter (no TC), and brighter (no TC).
It would be nice if the TS-E lenses became TS-EF - autofocus. I firmly believe that everyone's 24mm
(and 35mm...) lens should have tilt and shift, for when they are needed, but autofocus when they aren't.
Canon, with their great all-electronic mount, could easily allow this.
New Focusing Screens
We need a new focusing screen for shifted composition. Canon makes a screen with a grid, for verifying
perspective. This is great, except the TS-E lenses are all manual focus, and the grid screen doesn't have a
focus aid. There is a perfectly good screen with the usual split-circle, but no grid lines of any sort. So,
we are left estimating ranges and looking at the distance scale on the focus ring.
For tilted composition, the situation is even worse - the distance scale only tells us what is happening at
the image center. The scale might say 3 meters when the lens is actually focused at infinity on one edge
and 50cm at the other. Calculating lens tilt mathematically is practically a black art. I only know a
couple people that even know how, and they don't do it in their head on the scene. They guess a tilt, then
squint at the viewfinder trying to guess if it is sharp enough. This is hard at f/3.5 (the Canon 24mm lens)
or f/4.9 (same with 1.4x TC). I'd like a focusing screen with the normal split-circle focus aid, but instead
of merely the image center, have a circle (or major portion thereof) at each corner or perhaps centered on
each of four sides.
More Advanced Camera Electronics
An second alternative would be a camera that tells us what focus we're at, at the extreme edges of the
camera. This would involve the camera asking the lens 1) focus distance, 2) tilt, 3) rotation of tilt, and 4)
a constant or two related to focal length. The camera then calculates the focus distance extremes and
displays them on the LCD. A photographer who could estimate ranges accurately could adjust the lens
until the readout matches his estimates.
A third alternative would have two focusing rings for near and far focus. It would use Canon "E-M".
(This means that the focusing ring is just an electronic input sensed by the computer, that drives a motor
to change focus.) We would get a focus motor, and a second motor that tilts the lens appropriately. The
focus rings would be right next to each other, so normal operation would involve grabbing both
simultaneously.
http://www.photo.net/photo/canon/tilt-shift (8 of 9)7/3/2005 2:24:04 AM