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.

6 comments:

  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!

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  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

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

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  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.

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  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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