Select your longest focal length and compose a portrait shot fairly tightly within the frame in front of a background with depth. Take one photograph. Then walk towards your subject while zooming out to your shortest focal length. Take care to frame the subject in precisely the same way in the viewfinder and take a second shot. Compare the two images and make notes in your learning log.
As you page between the two shots it can be shocking to see completely new elements crash into the background of the second shot while the subject appears to remain the same. This exercise clearly shows how focal length combined with viewpoint affects perspective distortion. Perspective distortion is actually a normal effect of viewing an object, for example where parallel train tracks appear to meet at the horizon. A ‘standard lens’ – traditionally a 50mm fixed focal length lens for a full-frame camera (about 33mm in a cropped-frame camera) – approximates the perspective distortion of human vision (not the angle of view, which is much wider). A standard lens is therefore the lens of choice for ‘straight’ photography, which aims to make an accurate record of the visual world.
Portraits at Wide and Narrow Angles
This proved to be a much more complex exercise than I thought it would be and in truth I am very dissatisfied with the final images. I tend not to use zoom lenses and it has been a learning curve for me coming to grips with them. I actually had to buy a pair of zoom lens for this course as my usual preference is prime focus lenses. It was a bit of challenge to get the image scale of the subject in the the narrow and wide angle views to be at the same scale and in my final images I haven’t managed this!
I have however produced a pair of images that illustrate the point about how a wide angle lens close up to the subject produces a very different background. In my view an unnatural and exaggerated background which given how the human eye naturally sees a scene there is something quite alien about the effect. It does also demonstrate how the photographer can control what the viewer sees and these unnatural viewpoints or perspectives allow for creativity in my view.
In the first Image the focal length of the lens is 55mm (83mm in 135 format) end of the zoom range at f8. in the second image the lens is at 18mm (27mm in 135 format) and again set at f8. It is worth noting that the subject did not like that image at all!
There is a really interesting learning point for me here about how photography can present an unnatural way to view the world that for some subject (i.e. wide ange landscapes) can be pleasing but for others (i.e. wide angle close up portraits) can be very ‘jarring’ to the eye.