Objective: To show how changing the focal length of a lens and changing position can show a difference in perspective for a given subject. Use a zoom or two different fixed focal length lenses, take two pictures starting with the telephoto. Adjust postion and take a second picture using the wide angle. The larger the difference in the two lens’s the better.
Prior knowledge: I expect the two pictures will show quite a dramatic change in perspective. Also the apparent but not actual (as we learned from a previous exercise) compression in the foreground and background will be significantly different.
Preparation: I took a drive out and took some shots early in the morning while the sun was still low. This should add to the contrasts giving a better sense of depth. I used my Canon F2.8 L series 70-200mm and Sigma 12-24mm fisheye lens.
Process:
[85]
Canon 5D MKiii @200mm
The image above was taken at 200mm. The camera distance from the car was around 20 metres, although looking at the composition and perspective the viewer would think it to be closer to 5 metres. The trees and lamp post in the background appear to be fairly close, but in reality are at least 30 metres away. This ‘apparent’ compression is due to high focal length. A small aperture has made the central focus point the front area of the car.
[86]
Canon 5D MKiii @12mm
In complete contrast to the first image, this shot taken with a 12mm lens is verging on abstract. Moving forward and slightly to the side of the vehicle, the fisheye lens on a full frame camera has elongated the bonnet of the car, and the organic shape of the palm trees now appear to be leaning inwards. Actual distance from the camera to the edge of the car is only around half metre. Even with a wide aperture of f4.5, a larger area to the rear and road area to the right remain in focus. Parallax error is hard to avoid at such a wide angle.
[87]
Canon 5D MKiii @24mm
As with the other two images the camera angle has not being changed, only the positioning and focal length to adjust the perspective. A 24mm lens now gives a wide angle view without over distortion of the car unlike the 12mm and only a slight lean in the palm trees. Notice how the palm trees on the left gradually reduce their bending outwards and return to un upright position the further from the camera focal plane. Distance from the front of the car is around 2 metres. The lamp posts and buildings in the background now appear to be a lot further away compared to the shot taken at 200mm..
Conclusion:
Depending on what photographer wishes to achieve, a choice of focal length and camera position can make a dramatic effect on the images perspective. Backgrounds can be made to appear very close and compact using a long lens, or by simply changing position and focal length of the lens the same subject can be made to almost jump out of the frame. Simply changing lens’s and recomposing is not a substitute for moving the camera position for a better composition and change in perspective. A prime example would be moving too close to a tall building, thus creating converging verticals. Changing lenses without moving backwards and increasing the distance of camera to subject would not do much to reduce the converging effect. Many would argue the difference to the outcome of the final image by using a prime lens and moving position, as opposed to simply changing focal length which would not have the same effect on perspective.
O.C.A. BA (hons) Photography Degree Course 