I was troubled by my focal length calculations with the 14-54mm Zuiko lens. It seemed, using my method shown in https://pbase.com/sawilliams/computed_focal_lengths. When I used the same test on my manual lenses the calculated focal length and specified focal length came out spot on with fixed focal lengths and nearly so with a couple of old manual zooms. So, there must be some complicated business with the means of zoom and focus in the digital lenses. Also, I believe Olympus to be an honorable company and so they must mean something else by the specifications. I thought it must be that they specify the focal length settings with the focus at infinity. So I set up a method to try this. Using a tripod I made shots at 14, 35, and 54mm focal length settings. I then used the fact that for very distant objects the field width is inversely proportional to the focal length. I computed and marked the 14mm shot with the expected fields at the 35 and 54mm settings. The 35 field is marked in red and the 54 in blue. Then I cut those portions from the 14mm shot and scaled the actual 35mm and 54mm shots to the same pixel density. Then I made a side by side comparison. These are the results shown. Clearly the infinity setting is what Oly means by the focal lengths and they are as one expects.