Tuesday, January 26, 2010

Warning: f-stop experiment ahead

Poking around the house for warning labels, the most interesting one I could find was on this bottle of Peppermint Schnapps our neighbor gave us for Christmas. I just bought a prime, 50mm lens with f/1.8 and decided to try a couple of available light shots (at 4:30 on a gray winter afternoon). The best light I could find was on the floor near my living room window (hush, Ron...this was a legit experiment).

The minimum focal length for this lens is 1.5 feet, so I had to roll the bottle away from me far enough to get the small (maybe 5-pt.) type in focus. At an aperture of 1.8, the depth of field is so shallow that only a very small area of the label is in focus (image #1). If I drank much of this in one sitting, that would probably be my view (ha ha). In the second image, I shut down the aperture to 3.5, and the depth of field increased to a point where more of the label is visible. I tried to crop both images to a similar size, but as both shots are hand-held, I'm sure the original distance from the bottle changed somewhat.

Shot in Av (aperture priority), so the camera selected a matching shutter speed.

Image #1: Shutter speed 1/200, f/1.8, 50mm, ISO 800

Image #2 (below) Shutter 1/50, f3.5, 50mm ISO 800

Subtle differences, but visible if viewed full-size.


  1. When you enlarge the pics there is a huge difference! But, if every time you took a shot and then drank a shot, your eyes probably saw no difference! LOL What a great experiment - kinda like quarters but instead of flipping quarters - shooting shots! You are too fun Val! :) Great experimenting!

  2. Forgive Tammy, she is on a Photostagger not a Photowalk, like us true pioneers. Experiments is FUN@ Show use the Warning that says "Not for Human Consumption!" You did say Schnapps didn't you. What's wrong with good old Wild Turkey. Hope I can figure what I did wrong with my Prime lens I really liked it's clarity. Go to it girl (When your able to get back off the floor. LOL

  3. wow, great example, thanks for posting the experiment.

  4. Great illustration Val! This sort of experiment is such a great way to learn about our cameras. I like Ron's description of Tammy's Photostagger too - LOL.

  5. It is so much fun to get a new lens and play with it. Keep on having a great time!


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