There are three exceptions to the rule the original poster states. Here is a good analysis of the exceptions,
http://toothwalker.org/optics/dof.html
Thank you. Although I have not yet read the article thoroughly, I like the manner in which it has been organized, separately examining the various factors involved in Depth of Field.
Yes. It is definitely the best article on the topic of DoF anywhere on the net. I note the sidebox with the important point that...
"DOF should not be judged from background blur."
The closing statements are worth quoting as well....
""Finally, although the depth of field is a primary discipline of the photographic craft its importance should be seen in the proper perspective. It does not require familiarity with equations to confront the world with stunning photography. IMHO, from the theory of DOF, the most important ingredients would be the quest for the true hyperfocal distance to avoid backgrounds that are
just not sharp, and the art to disengage the subject from the background. The latter, however, is more a matter of blur and FOV control than DOF control.""
[I also approve of the staring role played by Gromit, who's ability to deliver a line I've found riveting in everything he has ever done.] ;-)
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Regards,
Baz
