Originally posted by hockmasm you HAVE to get this book,
Understanding Exposure. Its the best ever, I swear and so does everyone else on this forum.
Not me. I complain about it every chance I get.
Seriously, it's an okay book, but doesn't deserve all the love it gets. The basics of the three key factors in exposure are explained in a competent-enough way, but there's actually not much emphasis on
understanding what's going on, despite the title.
The book's explanation of aperture, shutter speed, and ISO as a triangle is an example of this problem. Sure, there's three things, and as we all know from Schoolhouse Rock, triangles have three sides — but really the relationship is mathematically
more linked than that: the factors are not like a triangle, but like the height, width, and depth of a
box (where the volume of the box is the amount of exposure you end up with).
When you double one parameter, you double size of the box — and the exposure of the photo. When you double the length of an edge of a triangle, what happens to the area of the triangle? (Break out the trigonometry!) And some combination are flat-out invalid — try making a triangle with sides of length 1, 2, and 7. But the exposure parameters aren't constrained that way at all!
That may sound like a nerdy obsessive complaint, but there's more to it. If one explains with this accurate geometric relationship (visually, even -- it's easy to show with diagrams), it both shows the surface level ("there's three things!") and opens up deeper understanding.
And the rest of the book follows from that: good beginner-level advice and tips, without much of a framework for deeper understanding.