9 April 2011

Focal lengths and different viewpoints

This is the reverse of the previous exercise; there the aim was to see how the size of the same object appears using lenses of different lengths, here the aim is to keep the object the same size (i.e. filling the frame) but change the perspective by changing lenses.

The suggestion was to use a building. I chose Ashton Court Mansion on a beautiful afternoon. This was perhaps not a great choice - the mansion is very wide relative to its height and consequently I had to be a very long way away to even get the whole building in on maximum zoom. The environs being hilly meant that the perspective changed too much as a result of natural rather than photographic features.

Consequently I used a 70mm focal length followed by 24mm and 11mm as follows:




All three images were shot with shutter speed 1/125 or 1/60 with a small aperture (f22).

We end up with the traditional record type shot for the first - a flat image that presents the mansion well with relatively low sun, albeit the sky (even enhanced) lacks colour.

 The third image was shot with very wide angle and we notice here:
  • the converging verticals. These can be manipulated out but the idea here is to leave them in to emphasise the depth - note how the near part of the building appears much larger then the far;
  • the foreground is nearer - note the top of the camera on the tripod is just visible at the bottom of the image so one is taking an image literally where one stands. By comparison, the foreground in the first image commences some way from the camera;
  • the sky is much deeper. Some vignetting was added to the corners but even without that we get a pleasing gradation of colour that helps balance the image;
  • The impression of looking upwards
The second image in my view represents the best balance between the perspectives. It is helped by the wispy cloud, which always adds to overall feel of an image taken with wide angle but for this subject gets a better balance between a flat record style image and a perspective that is too exaggerated.

From this lesson, I learnt that we should not always assume the most obvious focal length provides the most effective image - in this case a wide angle solution is not at all obvious given the nature of the subject but actually works well.