Exercise three: Focus at different apertures

The brief for this exercise was to choose a scene similar to the previous exercise (a row of things seen from angle) and take three images - one with the camera's widest aperture, another with a mid-point aperture and one with the narrowest.

To ensure that each image was framed identically I used a tripod. This was also necessary because the shots were taken in low light conditions and as such required longer exposures.

In order to get sufficiently close to the image I used a 12mm macro extension ring on my fixed 50mm Sony lens. This further narrowed the depth of field.

Widest aperture - 50mm, 1/6 sec at f/1.8, ISO 100

The depth of field in the first shot is extremely narrow, leaving only the 'X' key in focus. In fact, it's extremely difficult to make out any of the surrounding keys.

Mid-point aperture - 50mm, 3.2 secs at f/8, ISO 100

Having narrowed the aperture to f/8 the area in focus does indeed increase, but not significantly - parts of the 'Z', 'D', 'C' and 'cmd' keys are now in focus.

Narrowest aperture - 50mm, 25 secs at f/22, ISO 100

Although the depth of field is much wider not all keys are in focus, but they are all distinguishable. Those keys now in focus range from 'Z' right through to 'B'.

It was really interesting to see the effect that the macro extension ring had on the depth of field (narrowing it even further) resulting in a great effect on image 1.

The long exposure needed for images 2 and 3 meant that I used a remote trigger to fire the shots to avoid camera shake, although I did find using the camera's timer function worked equally well.

One camera option that I wasn't familiar with was BULB, which this exercise prompted me to research. I now know how to use this feature if a scene requires an exposure longer than 30 seconds.

Exercise two: Focus with a set aperture

The purpose of this exercise was to find a seen that contained a row of things at an angele, and to then take three images with the same aperture - one focused on the nearest point, one mid-point and one focussed towards the rear.

With such a tight composition, the lack of background (and therefore context) means the the subjects take a little figuring out. They are three fire buckets captured at Bury's East Lancashire Railway Station, and each in their own right has some appeal.

Mid-point focus - 50mm, 1/100 at f/2.5, ISO 100

The focus on the middle fire bucket (image 2) has good surface detail; it has the greater surface area of the three; and the parallel lines at the top of the bucket appear to give it a certain strength that the other two don't have. However, although there is a balance brought about by the central focus it's an uncomfortable one - it doesn't lead the eye of the viewer in a particular direction.

Distant focus - 50mm, 1/100 at f/2.5, ISO 100

Near focus - 50mm, 1/100 at f/2.5, ISO 100

This criticism can't be said of the other two images. The furthest focus (image 3) leads the eye from left to right/back to front and the closest focus (image 1) takes the viewer's eye from front to back/right to left.

Both images 1 and 3 are strong, but image 1 shades it for me. Although in western cultures viewing an image from left to right is an instinctive behaviour (see Gutenburg's Diagram), image 1 leads the eye from front to back and gives a greater sense of depth to the scene.

A stronger composition may have been achieved from the left hand side of the subjects; capturing both the flow from left to right and front to back.