Focal Lengths (1.2a)

Requirement

3 - 10 photographs

Purpose

To show the effect on angle of view, and therefore subject and image character, of using lenses with different focal lengths.

Technical learning

• Focal length of the lens determines the angle of view and has an immense impact on the character of the image
• Standard focal length (i.e. same length as the diagonal of the sensor or the film) gives a view that approximates what you see with your eye, although the eye loses sharpness at the periphery
• Lengthening the focal length of the camera, whilst making the subject appear closer, is not the same thing a moving the camera closer: the telephoto shot reproduces the centre of its equivalent taken with a wide angle lens

Exercise instructions

Pick a scene that is open with some detail in the distance. Use a tripod.  Take a sequence of photographs aimed in the same direction using different focal lengths.  Vary the composition slightly if this benefits the image.  Make a note of the focal length of each image.

Images and Review
In a spare hour whilst traveling home, I walked up from the rather dull Euston Station on a rather dull day to the marvel that is St Pancras station. Its front entrance is as grand as another's elsewhere in the world, surely. All that Victorian wealth, civic pride and self confidence! Pulling my Canon compact out of my bag for these just in case moments. A bit of struggle controlling the zoom to suit, though.

4.5 mm - capture the sweeping curve  (3/4 of a black car is a distraction)

5.9 mm - keep as much of the curve as possible (again the black car is a distraction)

8.2 mm - focus on the leading line by waiting for a pedestrian

12.3 mm - highlight the pattern and enliven with some human figures

22.2 mm - find the detail (the trio of lamps) from which to zoom in closer

29.7 mm - get closer to the lamp (pull pack to include 3 full arches would improve)

45.3 mm

97.2 mm

• Overall the effect of the zoom is to magnify the chosen sections of the original image:  the original perspective remains and so the magnified image is relatively flat, compared to shooting the same image closer to the subject with a wide angle lens.

Other Images

Here is an earlier attempt at this exercise, just round the corner from the main entrance to St Pancras Station. In reverse: telephoto to wide angle.

162 mm

81 mm

61 mm

26 mm

11mm