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Leave nothing but footprints

Exercise 3: Focus with different apertures

Objective:
To compare the difference in depth-of-field between images taken from the same viewpoint (tripod mounted) at different apertures.

For this exercise I used the same image set-up as for exercise two – the flowers and the pots at the garden centre.

In each case I focussed on a central point in the image and halved the aperture opening as I stepped through the aperture range. The lens I was using was the Sony CZ24-70 mounted on the Sony Alpha 900. This lens has an aperture range from f2.8 to f22.

Image set one – potted flowers

3.1: Aperture wide open at f2.8

[EXIF: Sony A900, CZ24-70 @ 24mm, ISO200, f/2.8, 1/1000 sec]

3.2: Stopped down to f5.6

[EXIF: Sony A900, CZ24-70 @ 24mm, ISO200, f/5.6, 1/250 sec]

3.3: Stopped down to f11

[EXIF: Sony A900, CZ24-70 @ 24mm, ISO200, f/11, 1/60 sec]

3.4: Stopped all the way down to f22

[EXIF: Sony A900, CZ24-70 @ 24mm, ISO200, f/22, 1/15 sec]

Image set two – pots

3.5: Aperture wide open at f2.8

[EXIF: Sony A900, CZ24-70 @ 24mm, ISO200, f/2.8, 1/2000 sec]

3.6: Stopped down to f5.6

[EXIF: Sony A900, CZ24-70 @ 24mm, ISO200, f/5.6, 1/500 sec]

3.7: Stopped down to f11

[EXIF: Sony A900, CZ24-70 @ 24mm, ISO200, f/11, 1/160 sec]

3.8: Stopped all the way down to f22

[EXIF: Sony A900, CZ24-70 @ 24mm, ISO200, f/22, 1/40 sec]

Conclusions drawn from this exercise

Depth-of-field increases as aperture increases (diaphragm gets smaller).

As aperture increases so shutter speed decreases. Interestingly, in both of these examples as the aperture is doubled (from f2.8 -> f5.6 -> f11 -> f22) the shutter speed is quartered.

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This entry was posted on Saturday, July 10th, 2010 at 19:58 and is filed under 01. A way of seeing, OCA Learning Log, TAOP Exercises, The Art of Photography. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.