When I opened the box from OCA I wondered if I should take the money and run - so much internet involvement with blogsites, websites' etc. However, nothing ventured, nothing gained.
Having been a keen photographer for 45 years, largely self taught, I thought I'd better start with the basics anyway, so I attempted the "Getting to know your camera" Project, with the exercise of focal length and angle of view.
I used a canon EOS 1D Mk3 and a 28-135 zoom. The focal length which co-incided with my natural vision for image size was about 65-68 mm. As the hypotenuse of an APS type H sensor is about 35 mm, I would have expected a corresponding focal length, but the viewfinder minimises the image by a factor of 0.76x, and this would indicate a normal view at 65 x 0.76 = 50 mm. This is still not near 35 mm so my eyes must be funny.
It was interesting to note that the same trick tried with a 35mm full frame film camera gave the same results, showing that the format doesn't change the angle of view of the lens, but only "crops" the image it produces.
Holding the A4 prints at the requisite distance to give a same size view gave distances of 45 cm for "normal", 23 cm for wide-angle (28 mm), and over 100 cm for telephoto (135 mm). 45 cm seemed a comfortable viewing distance.
I suppose if you are looking at perceived angle of view, 35 mm seems about right in that the content of the scene looks the same as in the viewfinder. However, my angle of view might be different from normal, in that my peripheral vision is more sensitive, looking at the edges of X-ray images for abnormalities, and for birds in the environment.
I didn't really find this exercise helpful.
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