Thursday 13 May 2010

Excercise 1 : focal length and angle of view

My first exercise so a little bit unsure as to what exactly to include but here goes

In this exercise we are asked to take three photographs of the same scene, noting the exact position from which the photographs were taken from. One image each at the widest and shortest available focal length , and one image to match what the eye was seeing.

Weather not too good so did this exercise in doors , setting the camera on a tripod to ensure i achieved the same position for each shot. Thought it was little difficult to do the image with both eyes open but got there in the end.

We were then asked to print each of the images on to A4 paper and return to the exact position where they were taken and view them adjusting the distance between the eye and the photograph so that the view was the same as on the print ,Finally we measured the distance of each of the three images photographs from eye to print.

focal length and angle of view (1 of 6)

The first photograph was with a focal length equivalent to the naked eye, so that is objects appeared to be the same size through the lens as they do through the eye.This image take with a Nikon 18-200 lens returned a focal length of 55mm.

focal length and angle of view (5 of 6)

The second image was taken with a Sigma 10-20 lens set at its widest focal length of 10mm

focal length and angle of view (4 of 6)

The third image was again taken using the Nikon 18-200 lens at its longest focal length of 200mm

After printing and viewing the images as required i came up with the following observations.

At 55mm focal length the measurement was appx 600mm from the eye.

At 10mm focal length it was impossible to measure as the image was virtually at my eye and would guess at a distance of 1mm .

At 200mm focal length the measurement was appx 1900mm from the eye

Conclusion

My cameras standard focal length in relation to how my eyes see the world is around 55mm. The distances of three images i took had a multiplication or division factor of around 10% in relation to the lens focal length.

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