Doug Peterson has a more complex method that uses the mask and LV that is systematic. He would be better able to explain it than I would and maybe he will see this.
When you break it out into words and detail every step this seems like a long/slow/tedious workflow. In reality I find it's very snappy, reliable, and almost surreally pleasurable of a process as compared to my days focusing ground glass where 1) you could not focus at shooting aperture but had to evaluate wide open or near wide-open 2) you had to specifically move the loupe to each area -- back and forth -- as you made any change.
Step 1: Establish sharp background
Option 1 - If the furthest important subject matter is infinity then simply set the lens to infinity*.
Option 2 - If the furthest important subject matter is closer than infinity then use Live View to focus on it (at near shooting aperture) or use iterative Focus Mask shoot-and-compare to establish the far subject matter as ideally-sharp.
At the end of step 1 take a moment to burn into your brain the amount of focus mask which is being indicated. Is it a few speckles, a lot of spots, a solid mass? This will be your reference for comparison in step 3.
Step 2: Add tilt based on experience/geometry, be conservative
There are some geometric rules of thumb (Jack can cover those) and some gut-feelings you'll develop after shooting with a certain gear combo and subject matter type. Error on the side of being conservative.
Step 3: Adjust focus point using Step 1 as reference for background. Initially (having just increased tilt) you will have less strong an indication of the focus mask on your background than in Step 1. Adjust focus and reshoot and you'll notice the strength of focus mask on the background increases. In a few itterations your focus mask will be the same strength as in Step 1. This is the ideal placement of focus for this amount of tilt.
Step 4: Evaluate foreground to determine if you have enough tilt
Now that your focus is set such that (with the current amount of tilt) the background is sharp, evaluate the foreground. If it's sharp then you nailed the amount of tilt. If it's a bit soft then increase tilt (be conservative) and repeat Step 3.
Step 5: Confirm
The first two steps should give you very high confidence that you're sharp everywhere. However, before I break down a tripod, or otherwise call it quits I'm always going to check the image at 100% and pan around the image to important areas of subject matter.
This process is high confidence, straight forward (if not "tactile" in the same sense as a view camera and ground glass), and can be done with a scotch in one hand. The places you can go wrong are:
- Guesstimating too high an amount of tilt in step 2. Anyone who has over tilted on a view camera knows the response of the camera becomes unintuitive and you'll start chasing your tail. Be conservative in your initial guess and worst case you'll have to add a tad more in step 4 and repeat step 3. Which, once you've done this method a few times, only adds 10-15 seconds to your process.
- If there are major changes in lighting between your reference shot in step 1 and your evaluation of the background in step 3 then this method falls apart. The entire process should take well under a minute once you're familiar with it, so it can definitely be used in dynamic lighting, but if lighting is changing very fast it will not work. In such cases using focus presets would be recommended.
Watching the focus mask grow between shots, and then recede a bit if you go too far is really pleasurable for me. It takes away a lot of the guess work and allows you to be very precise rather than end up very conservative (which you must be when on a view camera and making all judgements based on wide-open viewing and guesstimations of how much you can save by stopping down). A special shout out goes to the Arca R body which makes this process even nicer since the focus mechanism is so minutely accurate that you can easily iterate in small increments and - taking note of what number you're on in one frame - easily return to the previous increment if you determine you've gone too far.
*Which at some point in the past you've aready calibrated the offset for, shimmed, or mechanically adjusted (depending on brand of tech camera).
