I went to the National Gallery of Art to see the Callahan exhibit. See:
http://www.nga.gov/exhibitions/callahaninfo.shtm

I was less than impressed with much of his work. Wikipedia says, "He then spent almost every afternoon making proof prints of that day's best negatives. Yet, for all his photographic activity, Callahan, at his own estimation, produced no more than half a dozen final images a year.".

For all that shooting, there was not much that grabbed my attention and the photos, by today's standards, seemed poorly composed, uninteresting, and technically quirky (shadow detail was rendered almost black).

I did like his series of miniatures. I'm drawn to these little prints, perhaps because they force me up close to examine the photo. These miniaturess also seemed to be better in terms of subject material, composition and execution.

Still, pretty neat to see photos like this up close and personal!

Jerry W
Warrenton, VA