Calculating the standard focal length
Keeping both eyes open, objects seen through one eye should be the same size as that in the viewfinder.
The standard focal length of a 35mm camera is 50mm.
Over the past couple of years I have built up a collection of lenses which I have tended to use, without little thought to why I am using a particular lens. I would often take photos with whatever lens is on at the time, mainly because it’s a pain to keep having to stop and change lenses for the sake of one picture.
My arsenal of lenses for shooting pics includes:
Canon macro: 60mm f/2.8
Tokina wide-angle: 12-24mm f/4
Canon standard: 18-55mm f/3.5-5.6
Tamron telephoto: 55-200mm f/4-5.6mm
Canon telephoto: 90-300mm f/4.5-5.6mm
It took a while to find a suitable subject for this project. Eventually I decided on taking the view from my window, of the replica of Captain Cook’s Bark Endeavour.
1. Take a photo stood in one spot using standard focus.
I found that a focal length of 54mm seemed to be the standard view for my Canon 400D. At this length the subject is clear in the centre of the frame with the river Tees in view. At first I had stood on the riverside, opposite the Endeavour, but even at 54mm it was too close to get a good composition of the whole boat. I decided to go for a higher angle by standing on my balcony. This image could have been sharper, maybe if I had adjusted the shutter speed as it was getting cloudy.
2. Use a wide-angle lens and take a photo at its widest view, standing in the same spot.
The widest focal length gave a much greater perspective to the view, including more of the River Tees and the buildings along it. Wide-angle shots are some of my favourite type of photography because they provide more context for the subject and offer more depth of field. It’s as if I am standing further back from the subject than I am in reality. There is much more foreground brought into view by the wide-angle lens. I like how the footpath in the foreground leads the viewer towards the ship. However, this has also resulted in the objects in the background being de-emphasized, making it difficult for the viewer to see that the Endeavour is the intended subject. This image also appears to be sharper because of the larger aperture of f/4. I will find the wide-angle lens useful when space is limited, particularly photographing in crowded places and to emphasize the height of tall buildings. It will be useful when wanting to have a large area in focus. Subsequently, a wide-angle lens would not be appropriate for using selective focus to isolate a subject.
3. Take another photo in the same place, using a telephoto lens at its furthest setting.
The view through the telephoto lens, set at 205mm, has compressed the distance between me and the subject, which is now much closer and at a narrower angle. The depth-of-field within the frame has been reduced and there is less of the river in view (the foreground) However this has meant that only part of the Endeavour can fit in the frame. I also found it harder to avoid a blurred image due to camera shake using the telephoto lens, especially since the lens is heavier than the standard and wide-angle lenses I use. I will need to use a faster shutter speed next time to overcome the effect of camera shake, or use a tripod. A telephoto lens will be useful for getting close to sports action and wildlife. Another problem with telephoto lenses, that I read about in my manual, is that when photographing distant objects, a long lens shoots through a lot more atmosphere, which can reduce contrast and mute the colours.
Initially I had been putting off his project, because I wanted to get to grips with some of the other projects in the course and the first assignment. However I have found this exercise very useful and I’m sure it will influence the future choices I make when taking photographs, whether I want to isolate the subject, increase the foreground, or be aware of how to overcome camera shake. Therefore I can now appreciate the importance of using the most appropriate lens for the type of image I want to capture.