paleonet Digital Images and Depth of Field

[TomDeVrie@xxxxxxx]

Following the discussion of limitations in the depth of field of digital 
cameras, I wondered:

Can the photographer with a digital camera overcome this problem by taking 
two pictures of the same object, but with slightly different distances to the 
object (say, a 1 cm difference), and then blend the two images in Photoshop 
to take advantage of the portions of each image that are best focused?

I've started experimenting with this process and initial results are 
encouraging for a uniformly curved gastropod about 3 cm long.  Two pictures 
were taken with distances to obect varying by one cm.  Each image included a 
portion in focus and out of focus. One of the two images was re-scaled to a 
slightly larger size (e.g., 2048 to 2058 pixels) so that image dimensions 
matched.  An airbrush-eraser was used on two Photoshop layers, each layer 
having one of the images.

The final images need to be 'flattened' to create a single image.

Fortunately, there seemed to be no seam between the airbrushing done on the 
two components of the final image.  Airbrushing the same area produces a 
white patch, but the error can be caught when the airbrushing is first being 
done and remedied with an "undo" command.

It may be that a small degree of poor resolution near the boundaries of the 
airbrushed areas is an acceptable price to pay for much better focus along 
the entire vertical distance of the fossil.

Are there others on the listserve who have experimented more extensively with 
this approach?  Are there parameters beyond which the technique does not work?

Tom DeVries