Dear Brian,
The world is divided into "academics" and "techies".
The academics write erudite, gramatically correct, nonsense about inconsequential things like Shakespeare and "Global Warming", whilst techies write about things that really matter, like plumbing, cars, and photography, but can't always get the grammar or spelling right, because it doesn't really matter (just as Shakespeare himself demonstrated).
This is often obvious even in technical books dealing with photography where, even with the help of spell-checkers and (so called) editors, confusiion exists regarding minor matters, such as "effect" and "affect" and so forth.
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