Please do note when using a DoF calculator on the internet that these generally calculate too much DoF for 2 reasons:

1. They generally use the simplified DoF formula, which does not take FL into account in all parameters, and calculates (a little) too much DoF to start with. Not really a problem for middle to long distance, but there may be a more significant difference at shorter distances.

2. The standards for DoF were based on the technology of 1930, literally. A human eye generally sees much more detail than it would according to the standards used back then, defined as a maximum allowable distinguishable feature of 0.01 inch. This means that an item was supposed to be within DoF if on an 8 x 10 inch print viewed from a distance of 10 inch it shows a smallest distinguishable feature of 0.01 inch. Human eye acuity with 20/20 vision is approximately 3X better than that, making perceived DoF only about 1/3 of "calculated" DoF.

Example for point 2 using the extended DoF formula, focus distance 2 meters, 25 mm lens, aperture F/2:

a) Standard DoF calculation, using the full formula (which will give you a comparison against DoF calculators on the internet)

DoF start: 1.814 m

DoF end: 2.229 m

Total DoF: 0.415 m

b) DoF calculation based on 20/20 vision, using the full formula

DoF start: 1.934 m

DoF end: 2.071 m

Total DoF: 0.137 m

HTH, kind regards, Wim