I know that the human eye responds logarithmically while CCDs (the digital sensors used for astronomy) respond linearly. I'm guessing that film is roughly logarithmic, and the sensors used for digital cameras (which aren't CCDs, but I forget what they are) are roughly linear, but I could be wrong.

I'm sure you're right that our apparent depth of field is mostly due to how we change focus so quickly; I'm not sure about our dynamic range, but your guess seems reasonable.