I'm curious as to the usefulness of the new mirrorless cameras coming onto the market. As far as I have seen (in advert images), the user can determine what is being photographed only by viewing the rear screen.

First, if the contract stated the particulars, that's that. Secondly, if the 50 takes were each well worked out (as opposed to having been just 50 exposures), those 50 should be seen as the job and, at $6 for each of those efforts, the price is low. Remember the photographer who answered his employer's complaint about paying him too much for the job: "Well, I confess the rate seems pretty high--I took about 250 exposures and averaged a 250th of a second for each, so that is one second of work."

I tether mine to a nylon strap around my waist (strap has a common squeeze-release buckle). The strap has a sewed-on "D" ring to which a small carabiner is attached. A little (3") nylon strap (from a small LED flashlight) is linked to the camera's carrying bracket. To use the camera, I can either release the carabiner or, for quicker access, release the buckle of the waist strap.

Any sources for actual technical lens reviews, particularly for Canon?

Hello. I'm a DSLR photographer.