Back to the drawing board

Record high temperatures in Texas yesterday. Clear sky and sunny, so a good day to play in the back yard with the camera. I set up the experiment to test depth of field.

The results weren’t as straight forward as I’d hoped. I can detect the blurring but spacing the coffee cups along the tape measure didn’t give me the contrast I wanted. Plus, at greater distances I couldn’t be sure if it was blur or lack of resolution. I’d set the camera to Small quality, and had to look at 100% pixels on the computer.

I did, however, find a site DOFMaster that has a calculator. The numbers roughly correspond to my observations.

Particularly for the 80mm setting. It was clear that the near field was short, less than a foot in front of the coffee cup. The 35mm setting was harder, because you get about 1.5 to 2 feet in front and back. That was about the height of the total frame, so I couldn’t detect a lot of bluring.

The Wikipedia entry for Depth of Field has a lot of formulas. But it has a few example photos. It looks like F-stop is the critical parameter, along with subject distance.

I need to construct a better subject setting.