Fujifilm GF 45mm f/2.8 R WR Aperture Series with Focus Stack: West Walker Creek Meadow to Snowy Mountains
See my Fujifilm medium format wish list and get Fujifilm GF 45mm f/2.8 R WR at B&H Photo.

This aperture series from f/2.8 through f/11 shows the limitations of depth of field in a near-far scene. It is an excellent diagnosis of the extent of field curvature, and also discusses focus shift. It also includes a 4-frame focus stack at f/7.1 for comparison to f/11.
Aperture Series With Focus Stack: West Walker Creek Meadow to Snowy Mountains
Includes images up to full camera resolution from f/2.8 through f/11 plus a 4-frame focus stack at f/7.1.
If you’ve held off on focus stacking, but are interested in cameras like the Fujifilm GFX or the Hasselblad X1D or Nikon D850 or Sony A7R III—you had better get started with focus stacking yesterday, as I think the stacked image in this series makes obvious, as with the other series. See Getting Started with Focus Stacking.

GFX 50S + Fujifilm GF 45mm f/2.8 R WR @ 37mm equiv (45mm)
[low-res image for bot]