Optimizing Exposure

Lace and Forest. Clearview, Ontario. July, 2011 Fuji X100 @ ISO 400
A Bit of Background Information
In 2003 I wrote a tutorial titled Expose Right. To my knowledge this was the first generally available essay that discussed the realities of digital exposure, as opposed to that required for film. Since then the technique described has become known as ETTR( E xpose T o T he R ight).
The main points of that essay, summarized and updated, are as follows.....

A cameras sensor is an analogue device. When light hits a sensel (pixel) an analogue signal is generated. That signal is proportional to the amount of light received.

Just for fun, it's worth noting that film is essentially binary (digital) in nature. A grain of silver halide when exposed to light and subsequently developed turns black, or it doesn't turn black, depending on various factors including, but not limited to, the amount of light that it receives along with the amount of development. It only is when a large number of silve...