EYV 2 Exercise 2.1
Find a scene that has depth. From a fixed position, take a sequence of five or six shots at different focal lengths without changing your viewpoint.
Focal lengths were 70.0 mm, 100.0mm, 135.0mm, 200.0mm, 300.mm
All shots were f/5.6 and ISO 200
All were 1/2000 except the 300.0mm shot which was 1/1600
Of the five shots, the 100.00mm feels closest to the angle of view of my normal vision.
I experienced one thing that surprised me during this exercise. As instructed in the preamble to this section, I had set my camera to aperture priority mode, which I hadn’t used previously. I thought I would take advantage of the tripod to set a small aperture of f/25 and thus (I imagined) achieve a deep depth of field and therefore a good focus throughout the image. I focused on the church spire each time, but to my surprise the spire was not in particularly sharp focus in any of the five shots.
I then tried the lens’s smallest possible aperture f/32 and increased the ISO from 100 to 200, but the result was pretty much the same. I then decided to go to the other extreme and set an aperture of f/5.6. This time the spire was in much sharper focus, and while elements closer than the spire were now blurred, especially in the shots with longer focal length, I felt much happier with the overall result in terms of focus.
I wonder whether the reason for this may have been some movement of the camera during the slower shutter speeds of the attempts with smaller apertures (1/25 to 1/60 compared with 1/1600 to 1/2000 for the f/5.6 shots) – for example due to the tripod sinking into the carpet slightly and/or the strong wind that was blowing through the open window I was shooting from wobbling the camera slightly. Or perhaps I have not yet quite fully understood the inter-relationship of the various parameters and the way they work together.
f/5.6 1/1600 ISO 200
f/25 1/25 ISO 100
f/32 1/60 ISO 200
Update 27 January
Today I discovered that the screw securing the quick release lever on my tripod’s camera mount had become very loose. This may have been causing the camera to wobble slightly and could therefore account for the poor focus I experienced with slower shutter speeds during this exercise.