Category Archives: 05b-Focal length and different viewpoints

Focal Lengths and different viewpoints

Used from the same place, different lenses give different views. However, if you change your viewpoint as you change the lens, you can make a difference to the perspective. In this exercise I will demonstrate this.

I required a scene with enough space in front of it to allow a choice of viewpoint. The subject also required depth. I decided to photograph some golf carts, at a nearby golf course.

1. 300mm, F/5.6, ISO, 1/400s

Using my D5100 camera and a 70-300mm telephoto lens I set the lens to its longest focal length, 300mm. I composed the shot by filling the frame with the carts.

2. 18mm, F/3.5, ISO 100, 1/800s

Next, I changed my lens to a 18mm wide-angle. Looking through the camera viewfinder, I then walked forward to a point where the cart filled the frame and took a second photograph.

As you can see the resulting photographs vary significantly. The first photograph, taken at a 300mm focal length, shows the carts on their own. Other than the blurring grass in the background there are no clues as to the surroundings. The viewer is not made aware that the scene extends beyond the frame. The telephoto lens has influenced the perspective here so that both carts look to be of equal size despite being at different distances from the camera. This alongside the narrow angle of view has made the image clear and uncluttered. However, these elements make the image appear static and somewhat lacking in depth.

The second photograph was taken at 18mm. The wider angle shot shows the carts parked a few metres from each other. This distance is also noted by the differing size in the carts. The wide-angle perspective has made the diagonal curb appear at a wider angle, drawing the eye upward and across the image to the features in the left distance. There is a sense of depth to the image as the road and structures in the distance make the viewer aware that the scene extends beyond the frame.

Freeman, p100, Optics

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