Equivalent Field of View

[Zehn Ziegen]

Good-day,

I was wondering what "equivalent field of view" is and how it is calculated for different cameras? (e.g., "Used on the Sigma SD9 or SD10 [the Sigma 18-50 mm and 55-200 mm lenses] would provide an equivalent field of view of 30 - 85 mm and 93 - 340 mm respectively.", from http://www.dpreview.com/news/0310/03...madclenses.asp).

Thank you for your time.

Auf wiedersehen,

James

[Zehn Ziegen]

Never mind.