This exercise was to show the effect of changing focal lengths . I used my 18-105mm lens to focus on a two story buiilding some 600 or 700 feet away. I have earlier read Michael freemans The photographers eyes on his discussion on the topic and filling the frame of the viewfinder. A wide angle lens enhances linear perspective if used close to the nearest parts of the scene and can show a large foreground-to-distance ratio. A telephoto lens compresses these planes reducing linear perspectiv, if used from a distance.This weakens perspective (Michael freeman, 2007).
 |
| Fig 1: Shutter speed 1/3000s, Aperture F/9.5, Focal length 18mm |
The Fig 1 above was shot with the lens set at 18mm widest angle. The two story building in the background appears distant with a large part of the area shown to the left and right of the frame.
 |
| Fig 2: Shutter speed 1/6000s, Aperture F/5.6, Focal length 32mm |
At focal length of 32mm, the two -storey building begins to come more into focus. But the angle of view begins to increase. Notice that the wall in Fig 1 is no longer visible.
 |
| Fig 3: Shutter speed 1/6000s, Aperture F/5.6, Focal length 42mm |
 |
| Fig 4: Shutter speed 1/6000s. Aperture F/5.6, Focal length 48mm |
Fig 4 was shot at a focal ength of 48mm. . Notice the increasing angle of view with overhead tanks no longer in view.
 |
| Fig 5: Shutter speed 1/6000s, Aperture F/5.6, Focal length 62mm |
I am using an APC sensor camera with a focal length magnification of 1.5. This implies that the actual focal lengths should be x1.5. In the image above actual focal length is 62x1.5=93mm.
 |
| Fig 6: Shutter speed 1/6000s, Aperture F/5.6, Focal Length 80mm |
 |
| Fig 7: Shutter speed 1/6000s, Aperture F5.6, Focal Length 92mm |
 |
| Fig 8:Shutter speed 1/6000s, Aperture F/5.6, Focal Length 105mm |
The image 8 above was the maximum focal length achieved with my lens. But the difference in perspectives between the first and last images can be seen. In this last image , the storey building is clearly conspicious .
