Friday, December 28, 2007

So Just What Is In Focus Anyway?

I'm doing a "room shot" before the wedding guests hit the main reception ballroom. I want to show the table in the foreground and the entire background, usually remaining tables, in sharp focus. I need to use a wider aperture because I'm in a rush and I'm hand-holding the camera so I can move quickly - I choose F5.6. I've got a 10-22mm lens at 10mm on my 40D at F5.6 focused at 37 inches- what's really in focus? The answer might surprise you - everything is in focus from 18.5 inches to infinity!

Unbelievable isn't it - at 1 1/2 feet to the outer reaches of the galaxy - Carl Sagan would be impressed. OK, I know I'm a little "geeky" with this stuff, but check out DOFMaster right here - it's a link to a depth of field calculator. Just select your camera, focal length, and F-Stop and it will do the rest. You can even download it at no charge right here. Geeky or not, this is a great way to learn how your lens work at different apertures. There are lots of other goodies there too so check it out - a 5-Star find!

Footnote: I added the "Carl Sagan" link just for fun. I received his "Cosmos" DVD series for Christmas - then I hit one of the Sagan site links to the Planetary Society and found some truly stunning images under the heading "The Year In Pictures". It is a stunning collection of planetary images right here. Enjoy!

1 comment:

  1. Thanks for the link to DOFMaster. I am new to amateur photography and this was a very helpful tool.