How sharp do you want your photographs? Diffraction revisited (Part One)

Several years ago I ran a test on my camera to look for the effects of diffraction. Light bends as it passes through a small opening, the smaller the opening the more it bends. So the more you decrease the size of the iris of a lens (increase the f number), the more diffraction will blur the image.
Since the latest digital cameras have such small sensor elements, diffraction can start to be apparent at f11 or f13.
This is a nuisance. Often we want to go f/16 or f/22 to increase the apparent depth of field. What is the point of getting more depth of field on the one hand if the image goes blurry on the other?

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Oamaru exhibition postscript

The exhibition in Oamaru was very well received. The Colin Mckenzie Lounge is an ideal exhibition space with a lot of natural light and room for at least 25 large prints. The clan tartans on the walls added to the atmosphere, and the whole thing worked wonderfully.

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Talk: “Photography and the Heroic Age of Antarctic Exploration”

Venue: The McKenzie Lounge, Scottish Hall, Oamaru
Date: Thursday February 7th 2013 at 6.30pm

I’m giving this talk as part of the Oamaru Scott 100 and you are cordially invited.
The beginning of the twentieth century was quite similar to our own time in that new wave of photographic technology had swept the world. Anyone could and did photograph.
However there were important differences.

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