Camera: Canon EOS 550D
Lens: 18-200mm Telephoto Zoom f/3.5
Objective;
Take three photographs of the same subject, in this particular exercise, a row of items, similar to the previous exercise. The first image was to be taken at the lens' widest aperture, the second, at approximately the mid point aperture, and the final image at its smallest aperture. I set up my camera on a tripod as advised, and focused on one point, somewhere near the middle of the frame (8th pot from the left).
Photograph Number One; taken at f/3.5 (widest aperture)
Photograph Number Two; taken at f/11 (mid point).
Photograph Number Three; taken at f/22 (smallest aperture).
Photograph Number One; taken at f/3.5 (widest aperture)
In the first image above, it is clear to see the depth of field is shallow, the in focus area starts between the 3rd and 4th pots, and finishes between the 12th and 13th pots.
Photograph Number Two; taken at f/11 (mid point).
Sharp focus in this image is greater than in the first image due to the smaller aperture, thus giving us a greater depth of field. The DOF starts between the 2nd and 3rd pots and finishes between the 23rd and 24th pots.
Photograph Number Three; taken at f/22 (smallest aperture).
The depth of field in this final image is even greater than in the first two, however it is only noticeable in the foreground of the photograph. When I compared photograph number two and three, I could see very little, if any difference in depth of field towards the background of the images. In this image, the DOF starts at the far left of the image and finishes at around the 25th pot.
Conclusion;
During this exercise, I have learned that the smaller the aperture, (higher f number) the greater the Depth of Field (DOF), and thus a larger area of the image is in sharp focus.
A smaller aperture does not always give you the sharpest image, and a mid point aperture (approximately f/11 or f/13) can be a better option when photographing a row of items such as the ones in this exercise.
I have also learned that DOF seems to be more apparent in the foreground of an image (particularly in this exercise) than in the background.
The motion blur of the woman in the second and third images (who is placing a coin in each of the pots for good luck) is down to a slower shutter speed which was necessary with a smaller aperture, to achieve a good exposure.
For this exercise, I visited Wat Po Temple, Bangkok, where the famous Reclining Buddha is located (see below). My original idea was to use the reclining buddha as my main subject for this exercise, however I found it difficult to clearly see the DOF when I took the three images required, it was not until I walked around the temple, that I found the lines of pots, which proved to be a good subject.
