I have a few questions about using autoexposure lock and auto focus lock effectively. I think I've overanalyzed it by reading my instruction manual way too many times, and have gone crazy.
First, I've noticed that I can still change aperture and also exposure compensation (with the dial) even with this button pressed down. If this button "locks" exposure, then why can I still change these things? Isn't exposure determined by the aperture? And the exposure compensation...that really stumps me as to how I can still change it with the AE-lock button pressed.
Second, when is the best time to use the exposure lock feature?
Additionally, the auto-focus lock feature---you can also just hold down the shutter release halfway, so why is there the need for another button? Lastly, does the type of lens I use matter when it comes to focus-lock? If I want to focus on something not in the focus area, would using a lens with better bokeh help me out more than this feature? I hope I haven't confused anyone as badly as I've confused myself.