Doug Kerr
Well-known member
From time to time newcomers to digital photography ask about "equivalent focal length" notation.
I have just posted to my technical information site, "The Pumpkin", a new tutorial article, "Equivalent Focal Length", available here:
http://doug.kerr.home.att.net/pumpkin/index.htm#Equiv_Focal
It discusses this matter in a concise, not technically elaborate form. (From moi? Really!)
The article briefly reviews the joint effect of focal length and format size on field of view.
It next discusses how the diversity of format sizes in today's digital photography spawned a need for a way to easily compare, across different cameras, the effect of lens focal length on field of view.
Then the premise of the "equivalent focal length" convention is explained, followed by a discussion of how we use the "factor" for a particular camera to conveniently determine the equivalent focal length.
Next, there is a brief discussion of some of the names that are used for this factor.
Finally, there is a caution about the most common misconception involved in this area.
I have just posted to my technical information site, "The Pumpkin", a new tutorial article, "Equivalent Focal Length", available here:
http://doug.kerr.home.att.net/pumpkin/index.htm#Equiv_Focal
It discusses this matter in a concise, not technically elaborate form. (From moi? Really!)
The article briefly reviews the joint effect of focal length and format size on field of view.
It next discusses how the diversity of format sizes in today's digital photography spawned a need for a way to easily compare, across different cameras, the effect of lens focal length on field of view.
Then the premise of the "equivalent focal length" convention is explained, followed by a discussion of how we use the "factor" for a particular camera to conveniently determine the equivalent focal length.
Next, there is a brief discussion of some of the names that are used for this factor.
Finally, there is a caution about the most common misconception involved in this area.