Sunday 11 March 2012

Focal length and angle of view

The exercise was to take pictures of the same view using different lenses and different focal lengths.  On each occasion, the lens was set to its widest view, although with the macro and fisheye, there wasn't any choice.  The idea of the exercise was to understand how close or far from the subject the image produced had to be in order to be the same size.

DSC2034: views roughly equal at 55m (using 18-55mm lens)
DSC2035: 200mm has the widest view (using zoom lens)
DSC2036: widest view at 24mm but not in focus (using wide-angle zoom) - much smaller than eye view
DSC2037: as above but adjusting the fine focus - note further away than above

These pictures have the wrong white balance; shot indoors but on white balance accidentally left on sunny; s/b cloudy white balance? (no flash or indoors lighting)
Not 100% sure what the dial numbering on the fine focus for wide-angled lens means
DSC3039: tried same experiment with macro lens; auto-focused at 1m - (changed white balance to cloudy)
DSC3040: repeated with fisheye lens; no idea how to read dial, but the sideways 8 symbol was over the black dot.
Note to investigate how to read the dials on the lenses!

Then compared photos to see at what distance from the eye they are at the same size as the subject:
DSC2034 (55m): arms length
DSC2035 (200m): around 5 ft
DSC2036 (wide angle zoom 24mm): held at my eye
DSC2037 (wide angle zoon 24mm plus finely focussed): right against my eye
DSC2039 (macro lens 1m): around 2ft
DSC2040 (fisheye): impossible to get the same size proportion, even right against my eye

This exercise has shown that although I know how to use a lens, or which lens I want to use, I'm not sure how to read the dials on all of them.

Also can't get this blog to upload photos in the right order......

DSC2034


DSC2039
DSC2040

DSC2035

DSC2036

DSC2037

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