Find a scene that has enough space in front of it to allow a choice of viewpoint, from near to far. Start with the longest telephoto lens and make a tightly framed composition. Then walk forwards in a straight line until you can fill the frame with the same subject at the widest angle setting, and take a second shot. Compare the two.
Canon EOS 650D with EF 18-200mm f/3.5 lens.
I chose the fountain in the grounds of Castle Howard and followed the straightforward instructions in the brief.
The first shot was at 200mm focal length, and it had the effect of dramatically compressing the distances between parts of the image; in reality the backdrop of the house itself was as far away from the fountain as I was on the other side, but in this image it appears to be immediately behind. Similarly, the water cherubs on each side look to be adjacent while in fact they were positioned one on each corner – so the true front-to-back distance was equivalent to the left-to-right distance you can see here.
Filling the frame with the same subject with my lens at its widest focal length of 18mm gives a very different feel. The subject has gained more depth and more closely resembles its real-life dimensions. The cherubs are clearly spaced on each corner of the fountain base, and the house has receded into the distance, allowing a backdrop of sky. The relative position, size and distances in this image are much truer to life and therefore easier to assimilate.
What I’ve learned:
Zooming in to a long focal length has a significant effect on the perceived depth in the image; it can produce a very flat image where the all parts of the image from foreground to background seem to be very close together. Wide-angle shots, on the other hand, more strongly convey a sense of depth. The resulting pictures from these two extremes are very different in feel and character. This is something I must start to take into account when deciding the focal length to use and the viewpoint from which I want to take a picture.