Take nothing but pictures
Leave nothing but footprints

Exercise 10: Focal lengths and different viewpoints

Objective:
To take a series of pictures with different focal lengths from different viewpoints that demonstrate how changing focal length can impact the reading of the picture.

These pictures were again taken with my Canon G10  at Eccles beach while on holiday in Norfolk.

The brief from the study guide was to find a subject that filled the frame and to shoot with a wide angle and a telephoto lens. I will be returning to this exercise with shots that exactly follow the brief but as soon as I saw this potential subject on the beach I knew it would be ideal to show the difference that focal length can make to the outcome of a shot.

The main subject is the top of one of the poles the erosion defences on the beach – the rest of it now buried under sand. In the background are the dune that grow on the main sea defences. Three pictures were taken: the first at approximately ‘normal’ focal length (13.76mm – 63.1mm equivalent) then zoomed out at 6.1mm (28mm equivalent focal length) and finally zoomed in at 30.5mm (140mm equivalent).

In each shot I attempted to keep the height of the post the same using the ‘rule of thirds’ grid that is presented on the G10 display – allowing us to see how the changes in focal length affect not the main subject but the surrounding context.

The images (click on images to see larger versions)

10.1: Shot on a Canon PowerShot G10 at ISO80, f/5.6, 1/125 sec at 13.761mm

10.1: Shot at 13.761mm (63.1mm equivalent - approx 'normal' focal length)

10.2: Shot on a Canon PowerShot G10 at ISO80, f/5.6, 1/160 sec at 6.1mm

10.2: Wide open at 6.1mm (28mm equivalent)

10.3: Shot on a Canon PowerShot G10 at ISO80, f/5.6, 1/125 sec at 30.5mm

10.3: Shot at 30.5mm (140mm equivalent)

Conclusions drawn from this exercise

The initial shot at ‘normal’ focal length gives a good approximation of the relative sizes of the scene to the naked eye and is therefore a good baseline against which we can compare the wide open and zoomed in shots.

At 28mm equivalent we see a number of effects of the focal length. The foreground dominates to the extent that the beach appears to slope quite dramatically while much more of the background is captured in the wide field of view. The perspective is distorted such that the background sea defences and dunes appear much smaller.

Conversely, at 140mm equivalent we see a much narrower field of view with the dunes in background magnified – appearing much larger than in the wide open shot or the ‘normal’ shot.

Thus we can conclude that not only does focal length have an impact on field of view but also on magnification – with distant objects appearing smaller while zoomed out and larger when zoomed in.

Adjusting the composition

For the purposes of the exercise I positioned the erosion defence post right in the middle of the frame – something I would not normally do. I did love it as a subject though – the bright red colour set against a background on more muted dull colours. Also, given the heavy skies the possibility of getting a dramatic shot was very good.

After a bit of re-composition and (a little) post processing this is my favourite shot of the scene. I hope you like it as much as I do :-)

Shot on a Canon PowerShot G10 at ISO80, f/5.6, 1/160 sec at 18.098mm

My favourite shot of the day

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This entry was posted on Wednesday, August 4th, 2010 at 07:57 and is filed under 02. The Frame, OCA Learning Log, TAOP Exercises, The Art of Photography. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.