So you weren't serious before? If not, then you could be misleading those who are unsure, which is not useful.

However, I'll assume it is a serious question and that you're using a 55mm lens. If you set it on f11 you could actually focus on infinity and DOF would stretch down to 8.44m but if you do that you're wasting the DOF beyond infinity, so rack back to focusing on 10m and you will have DOF at f11 of 4.62m to infinity.

Nobody needs to go to those lengths when there is a well established rule of thumb that works.

I suggest that anyone who doesn't believe the simple way just has a go and finds out for themselves.

Far better to just make some images rather than getting bogged down with charts.

Focused on 10m (30 feet) a 55mm lens has a DOF from 3.71m to Infinity.

Not too shabby as an approximation. Comes down to 3.01m on f22.

The figures I quoted were only to give an idea of the scale of the measurements, not to suggest they were actual accurate figures.

The point is made that everything would be within the DOF. If it didn't work, then generations of photographers would have been wrong.

Nice vibrant shots of an interesting subject. The choice of lens was perfect as well.

I'll start again from the beginning. This is a simple "rule of thumb" (approximation if you like) for getting as much of a scene in focus as possible.

Set a small aperture (maybe f16, maybe f22)
Focus on a point one third of the way in, between the point closest that you want in focus and the point furthest (often infinity).

So if the closest point you wanted in focus was 30 feet and the furthest was 120 feet then you focus at about 60 feet.

Obviously citically a lens always is focused on one distance only, but the circle of confusion allows some leeway that we call depth of field.

This also assumes something close to a normal lens. It's not going to be much use with a 1000mm f8.

Did you remember to also manually focus on the spot you wanted to take the picture? When the subject arrives at that spot the AF system thiks it's in focus and the shutter should release.

The one third in works perfectly well in the circumstances it refers to - that is using small apertures at moderate distances, such as in landscape photography.

In the same way the "sunny 16" rule also works extremely well, but the photographer needs to know how to apply it.

What a weird lens test.

Sample variations aside, this also depends on the design parameters of a lens. Most 24mm lenses would actually normally be used at small apertures, so it could be that it was designed to peak around f8-f11 and be at its best where it was expected to be used.

Although no doubt there are some exceptions, relatively few 24mm images are shot at f2.

Photographers can get lots of inspiration from cinematograhy, sometimes in unexpected or forgotten places.

I rather like the style of "The Avengers" (The TV series) where many scenes are actually set up like still images. A typical example is in the episode "All Done With Mirrors" where there's a terrific shot of a murder victim seen through the broken lens of his discarded glasses.

Scenes like that can give ideas for composition and that is very much something that Pentax users can gain from.