Reviewing camera equipment often requires us to compare specifications because each system is different, beginning with the sensor size. One of the most common comparisons involves focal length equivalence, a topic that often generates some confusion. The most recent example we’ve encountered concerns the new Olympus 300mm f/4 Pro (see our review here) that gives the equivalent focal length of 600mm on a full-frame camera. Not only have I read many discussions, but I’ve also received a few comments stating that this comparison is not fair and that a 300mm is a 300mm lens regardless of the sensor that resides behind it.
Is it correct to compare the M.Zuiko 300mm to a 600mm lens designed for a full-frame system?