What is "Phase Detect Autofocus?"

[TCampbell]

Typically when using AF I use the view finder, when using manual focus I go to live view, magnified, with Focus Peaking active. Focus peaking available on several model cameras takes your ability to fine tune manual focus to a new level of sharp by allowing you to "see" a visual marker of the parts in focus.

I own a couple of tilt-shift lenses (24mm & 90mm) and tilt-shift lenses are always manual focus. When tilting the plane of focus, it can be challenging know when you've adjusted the plane to make all the details you care about in good focus.

Focus peaking is a nice aid. I also found a tethered capture app (Kuuvik Capture) that does focus-peaking on your monitor with some pretty cool specific support (some designed with tilt-shift lenses in mind). They let you click points on your monitor preview and open up sub-windows showing a magnified view of each those points (simultaneously... and with focus-peaking enabled if you want) so that you can really dial in focus & tilt adjustments to nail the shot.