If you want to try it, try this:
-Find a distant horizon line with a good range of detail long enough to cover
the diagonal of the film (a city-scape from a high point, a lake edge with
cottages and boats, a wooded hilltop against the sky, etc. work well).
-On Plus-X exposed at 100 (and/or Technical Pan at 20 or Tri-X at 400) and 100
ASA color negative (I can process the film), expose the following frames in manual mode (if possible), adjusting the shutter to keep the exposure constant:
* AT f2.8, one vertical with the right side high running the detailed horizon
along the top edge of the frame, after carefully focusing the lens.
* Without changing ANYTHING, repeat the same exposure with the camera turned
up-side-down (this allows checking for good alignment, since the four corners
are comparable and the opposite sides have identical subjects just across the
film frame-line [and focus error will be identical in both frames]).
* Run a sequence from f2 through at least f5.6-8 without changing focus
(repeating this with a second focus can be useful, if focus is in doubt),
running the horizon line from one corner to the diagonally opposite corner
(if you repeat the sequence, reverse the direction of the diagonal, which
will give an added check on more of the frame). This shows how sharpness
exposure, and illumination change with aperture and across the frame. Since
most good lenses perform about the same in the center at f5.6-8, that point in
the frame can be used as a reference for comparison with other parts of the
frame, with parts of the frame at other apertures, and with other lenses.
* On a flat textured surface (gravel, train tracks, grass, etc.), aim the
lens straight down (try to figure out where the spot directly below the lens
would be, and put the center of the frame there), and shoot a sequence from
f2 through f5.6-8 (but this time, refocus with each frame since it is hard to
hold an exact distance). This shows performance at mid-close distances (I
sometimes add minimum-focus, and 2-300' checks to this for particular lenses).