On 2009-02-04 10:59:04 -0800, Pat said:

On Feb 3, 3:35*am, (Ray Fischer) wrote:
Mr.T MrT@home wrote:
"Sir John Howard" wrote in message
This is fine if you want to reduce depth of field. However, a tilt/s
hift
lens is often used to increase depth of field. You cannot do that in
Photoshop with a single image.

A tilt/shift lens is primary used to correct perspective. A lens apert
ure
controls depth of field.

Partly true, a simple tilt-shift lens is not a complete substitute for a
full view camera with tilting film back and lensboard which DO allow the
depth of field to be non parallel to the film/image plane.
And you cannot do that with lens aperture alone.

I've taken photos that had subjects from six inches to infinity, and
even at f22 it's hard to get everything to be sharp. *Of course, TS
lenses tend to be too expensive for the occasional need.

--
Ray Fischer * * * *
*

There is software to handle the extended depth of field. You take a
series of pictures and merge them. Say you start by focusing 6 inches
out. Then if your DOF ends at 12", you take another picture and focus
8 inches out. If your DOF then ends at 16", your next picture is at
12" or so. You then merge the photos together and get one picture
with extended DOF. I've never used the software but I've read
articles about it and it's pretty slick (and easy).

It is the same concept of bracketing exposures and blending the images
to give a larger dynamic range.

Sure, but it is not always possible to take multiple exposures so that
you can merge them together.

After all, you can take two exposures and effectively double the pixels
in your camera, too. So why bother getting a 24 megapixel camera when
you can get nearly the same resolution with two 12 megapixel exposures?
Maybe the bride won't sit still?

--
Waddling Eagle
World Famous Flight Instructor