What’s the true focal length multiplier for Micro Four Thirds?

It is often stated that Micro Four Thirds cameras have a 2.0 focal length multiplier. In other words, a 14mm lens on Micro Four Thirds is said to be equivalent to a 28mm lens on a full-frame camera.

The problem with this comparison is that full-frame has a 3:2 aspect ratio, while Micro Four Thirds has a 4:3 aspect ratio. If you crop one picture or the other so that the two pictures have the same aspect ratio, you will get a different focal length multiplier.

If you crop the full-frame image to 4:3, then the focal length multiplier is 1.85. So a 14mm lens on Micro Four Thirds becomes equivalent to 26mm on full-frame.

If you crop the Micro Four Thirds image to 3:2, then the focal length multiplier is 2.08. So a 14mm lens on Micro Four Thirds becomes equivalent to 29mm on full-frame.

One thought on “What’s the true focal length multiplier for Micro Four Thirds?

  1. That’s one of the features I like about the Panasonic DMC-LX100 (and the LX7, before it) because you can change the aspect ratio, to better suite the picture you’re about to take. Many people complained about this switch, and some just didn’t like it, but once you use it, you’ll quickly see the benefits of this feature. … JP

    Like

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s