St3v3M Loc: 35,000 feet

Is this helpful and how do you use it?

"Take a look at your camera, and there’s a good chance it’ll have this symbol: Φ — a small circle bisected by a long line that looks like a hieroglyph of Saturn. If you’ve always wondered what it means, today’s your lucky day: it’s called a “film plane mark” (or “focal plane mark”, depending on who you ask), and indicates exactly where the film (or sensor) plane is inside the camera body. One reason the mark is useful is that macro photographers often want to determine the exact distance between their subject and the film plane, and the mark can make this calculation much easier."
-- posted from http://www.petapixel.com/2012/06/01/ever-wonder-what-this-symbol-on-your-camera-means/

travlnman46 Loc: Yakima WA

Hi St3v3M: Very interesting information... I learn something new here everyday... Thanks for sharing...

Nikonian72 Loc: Chico CA

Minimum Focusing Distance (MFD) is measured from sensor plane to subject, and is listed as a stat with most lenses. Macro-photographers are more concerned with Working Distance (WD), which is measured from lens front element to subject.

Leonardo Loc: The Garden of England

I'd always known what it meant, but never why I needed to know!

Merlin1300 Loc: New England, But Now & Forever SoTX

Most DSLRs have the tripod mounting screw located precisely centered on the sensor plane.
This makes alignment of sequential panoramic shots much easier.

mrblackett Loc: Bloomfield, CT

The Nikon D800 manual explained this.