I shot the photographs at all
full f stops between f/4 and f/22, but only f/4, f/11 and f/22 are shown here
to demonstrate the effects observed. The
focus is on the spine of Douglas Adams’ ‘The Hitchhiker’s Guide to the Galaxy’
as that was the story I wanted the images to tell, and the shutter speed at
each aperture was noted to record the reciprocal relationship between them ..... as the aperture decreases, the shutter speed increases
to maintain the same exposure. Natural
light was used, the camera held on a tripod and the shutter fired with a
remote.
Shutter speeds for each
aperture were: f/4 at 1/15sec : f/8
at 0.5sec : f/22 at 2sec
The areas of acceptable
focus are annotated on the images with white arrows. The first image, taken at f/4, was only
acceptably sharp immediately around the point of focus and told a different story
to the images at smaller apertures. The
narrowest depth of field took the eye to the Douglas Adams' books and held it
there – so the image seems to be about these books only. The image at f/11 was soft at both ends of
the row, and although still taking my eye to the middle, it had lost the
emphasis on the Adams’ series. At f/22
the image was just a picture of a row of books and lacked emphasis on any particular
aspect, hence failing to emphasise the point of the image.
f/4 |
f/11 |
f/22 |
Canon 5D Mk II with 24-105mm f/4 L IS
lens
80mm | ISO400
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