Brief
Does zooming in from a fixed viewpoint change the appearance of things? If you enlarge and compare individual elements within the first and last shots of the last exercise you can see that their ‘perspective geometry’ is exactly the same. To change the way things actually look, a change in focal length needs to be combined with a change in viewpoint.
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.
Execution
In the previous exercise, we have seen that the ‘perspective geometry’ remains the same when zooming in on a scene from a fixed viewpoint, meaning that individual elements remain the same and zooming in and out does not change the way things look – the individual elements remain exactly the same. In this exercise we are now going to change the viewpoint and see the elements changing in the scene. In the first image taken at 105mm, the overall background is more inclusive, more perspective can be seen whereas in the second image the viewpoint is changed and so is the focal length at 24mm, the background now has the gate at the back and the car in the right visible, even though the same cannot be seen in the first image. These are elements that become visible even as the background gets more burred and out of focus.
The common camera settings for both the images below are:
- Camera – Canon 1DX Mark III
- Canon EF24-105mm f/4L
- ISO 100
- Aperture Priority Mode
- Exposure – overexposed by 1/3 of an f-stop
- f4
ISO 100 | f1/80s | f4 |@105mm ISO 100 | f1/100s | f4 |@24mm
I tried this again in a second attempt in another location. In the first image taken at 105mm, the overall background (besides the lamp on his head which I couldn’t avoid as they are in a line at every point) more depth is visible and more perspective can be seen whereas in the second image the viewpoint is changed and so is the focal length at 40mm this time, the background now has the greenery on the right in between the pillars visible which was not visible in the first image and the lamp disappears as well.
The common camera settings for both the images below are:
- Camera – Canon 1DX Mark III
- Canon EF24-105mm f/4L
- ISO 100
- Aperture Priority Mode
- Exposure – overexposed by 1/3 of an f-stop
- f5
ISO 400 | f1/125s | f5 |@105mm ISO 400 | f1/250s | f5 |@40mm