Making Sharp Images previously discussed several key areas involving depth of field:
- What are F-stop and T-stop?
- Format-Equivalent Depth of Field and F-Stop.
- Depth of Field at the Periphery
- Depth of Field with Real Lenses (including Delay in DoF by Double Image Bokeh and Delay in DoF by Color Divergence).
I find these subjects challenging to explain in ways avoiding jargon and too-involved technical aspects, and they took me myself some years to grok. Yet they are extremely useful in practice, particularly for those shooting cameras of different format sizes (e.g., Micro Four Thirds and/or APS-C vs full frame 35mm vs medium format).
Real lenses on real cameras show it best
But now I am really gruntled* to demonstrate and thus demystify how depth of field has its f-stop format-equivalence.
* Nearly as gruntled as my purring house cat proudly presenting a fresh-caught garden gopher on the doormat. Good kitty. Mitigated by my wife getting disgruntled with me for borrowing all her Pellegrino. I explained that a case of red wine with just the right label (ahem) would be even better, but that idea flew about as well as a hog.