P&S Aperature Equivalency

Bob Fiske · Mar 30, 2005

The aperature range of my G5 ranges from 2.0 - 8.0. Because of the small size of the sensor it is difficult to tell what these aperatures are equivalent to on an SLR lens. Anybody know?

ksmattfish · Mar 31, 2005

f/# = focal length divided by aperture size (50mm lens divided by a 25mm aperture = f/2)

Aperture doesn't change related to film format or sensor size.

The angle of view of a particular focal length varies with film format/sensor size.

Bob Fiske · Mar 31, 2005

Maybe I don't understand my own question. I need to know DOF equivalents. If I'm not mistaken, the DOF at a given aperature is not the same as it would be on a camera with a larger sensor. Does anyone know, for example, what the DOF is at say 8.0 for this camera?

ksmattfish · Mar 31, 2005

Bob Fiske said:
Maybe I don't understand my own question. I need to know DOF equivalents. If I'm not mistaken, the DOF at a given aperature is not the same as it would be on a camera with a larger sensor. Does anyone know, for example, what the DOF is at say 8.0 for this camera?

Besides f/8 I'd need to know lens focal length, and camera to subject distance (or focus distance).

Search for "DOF calculator" on any search engine and you will find numerous sites that can help you calculate a DOF scale for your camera. Most have a calculator where you can input your specs, and it will come up with a table for you. Some of them do have a format size input. Some even make a custom DOF scale for your camera that can be printed out and assembled so you can carry it with you.

The biggest problem you're going to have, assuming your camera has a zoom lens, is that you'll have to calculate a different table for each focal length.