This aperture series from f/2.8 through f/13 shows the separation powers of wider apertures along with the total inadequacy of f/13 to deliver depth of field in a near-far scene like this.
To contrast f/13 depth of field, an 8-frame focus stack at f/10 is included. Worth noting is that not all frames need be stacked; as an aesthetic choice the full depth is stacked, but it might have ended, say, at the rear of the boulder—one need not include all frames in the stack. Additional comments on focus shift round out this as a very instructive example.
It is also a good series for seeing bokeh.
Includes images up to full camera resolution from f/2.8 through f/13 plus an 8-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.