What does this mean?

[CanonCam]

I am in the middle of reading a book regarding exposure settings (aren't they all about exposure in some way or another?) and came across a phrase I don't understand...Distance Settings

The phrase was used in reference to getting proper depth of field when using smaller apertures. Specifically, reference was made to prime lenses having depth-of-field scales (I don't have any prime lenses so I'm not sure what these are/do). Since zooms (at least the zooms I have) don't have this scale, the reader is told to use "Distance Settings" to set the depth of field before shooting. Anyone know what this means?

Thanks for the help!

[RossW]

I can answer part of this, I hope. The depth of field scale on a lens is an engraved mark which indicates the distance to the object being focused. On either side of the mark are numbers indicating f-stops. They might look something like this:

16 11 8 4 I 4 8 11 16

where the I is the index mark. Let's say it lines up at the 15-foot mark on the focus ring. The f-stop numbers will also line up at various distances on the focusing ring. The 16s may line up on the 8-foot and infinity focus indicators; the 8s might line up on the 10 and 30-foot focus indicators, etc. They would tell you that you'd get decent focus between 8-feet and infinity at f/16, from between 10 and 30 feet at f/8, etc.

I'm not exactly sure what the author is trying to say about "using Distance Settings" if it isn't related to these scales... unless it could be the hyperfocal distance??

Hope this helps a bit.

[CanonCam]

Thanks RossW, that helps. What is hyperfocal distance? Sorry to ask questions that everyone else probably already knows...

[RossW]

In very non-technical terms, the hyperfocal distance is a "sweet spot" focus setting that gives the greatest useful depth of focus. It's thought of as sort of a "default" focus so you could can get off a very quick shot without taking time to focus accurately, but still have a good chance of an OK photo. It's discussed in great (and accurate) detail elsewhere in the forums, but I'll give a capsule of it from a book I just referred to for the example I gave above.

Set the lens for focus at infinity. For a given f-stop, use the depth of field scale to identify the closer distance that should be in focus. Then re-set your focus to that distance, and the aperture for that f-stop. Your sharpest focus will be at that point, of course, with hopefully reasonable focus across a wide range. This method assumes manual focus, naturally, and either a manual or aperture-value exposure in order to maintain the setting you "calculated" for the hyperfocal distance.

(Still no guarantee that reflects what your author was referring to.)

[CanonCam]

Great! I really appreciate the help!

[Curtis N]

What is hyperfocal distance?In technical terms, it's the distance at which all objects from half that distance to infinity are "acceptably sharp". It varies according to lens focal length, camera format, and aperture.

Some good info here (http://dofmaster.com/hyperfocal.html).