I had a few failed attempts at this exercise in various graveyards and marinas, probably because I was choosing subjects that were too far from the camera and in which the separate elements were too distant from each other. I therefore searched for a subject that I could photograph close up and which had sufficient depth to emphasise the impact of changing the focal length on how much is in focus. A young palm tree at the edge of the swimming pool of a hotel in Lanzarote seemed promising. I could stand over it, focus on the seed pods in the centre and keep the ribbed leaves in front and behind of them in the frame. I hoped the ribbed leaves would emphasise the degree of front to back focus.
I used a 40mm fixed focal length lens, largely because it is very small and light, therefore not putting my baggage allowance under strain. The camera was set on aperture priority and I selected four apertures; f2.8, f8, f11 and f22. I chose both f8 and f11 simply because I wasn't sure which best represented the mid-point. I did not crop the images when editing.
f2.8
f8
f11
f22
The sequence of shots clearly shows that the narrower the aperture the greater the depth of field. The difference between f2.8 and f22 is very marked. I was surprised at the difference between f8 and f11; there is a noticeable difference in the amount of the front leaf in focus. The f8 shot also shows that the amount in focus behind the focal point is greater than the amount in front.
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