Focus & f-stop

Yesterday Marjolein & Martijn gave me the Dutch version of the National Geographic Photo Guide as a birthday present and because I helped paint Martijn's apartment. Today I learned my first thing, that f-stop changes the depth of focus. I never knew, but you can see the difference in these photos.

The left is with f/3.5 and 1/80 exposure time, which gives the same lighting as on the right with f/8 and 1/15 exposure time. However as you can see, if you make the diafragma bigger (f/3.5) the focus has a shorter range than with a smaller diafragma (f/8), because the background in the left pic is more of a blur than in the right pic. I thought this was a pretty cool thing to learn :)


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Photoshop:
just putting 2 pics in one pic.