This video may be a good primer for Depth of Field and may be a good one to show during the club meeting. It is 6:13 minutes in length.
Part 1- Short Lens by Mike Browne
And here is the other part of Mike’s demonstration where he pulls it all together
Part 2- Long Lens by Mike Browne
This one is pretty basic and is fairly easy to understand
By Cam Crunch
This one is a bit more technical and is explained with drawings. While a little harder to get your head around, it may help to shed light on the concepts in a different way.
By Dylan Bennett
Some good tips on shooting photographs that require a very wide depth of field.
(Hint: Also, search YouTube for “Hyperfocal Distance”)
Some good demonstrations on shooting portraits with a shallow DOF
By Adorama TV
There are many Depth of Field Calculators available online and in Apple and Android environments. You can simply dial in your Camera Sensor Size, Aperture Value, Focal Length and Distance to Subject. The DOF calculator will give your DOF for those values.