"SIDEBAR. Since a Four Thirds sensor already produces a 2X field of view as compared to full frame 35mm, this means that in ETC video mode the focal length marked on the lens is actually 5.2X what it would be in full-frame 35mm terms. So the long end of the new 100-300mm zoom is equivalent to 1,560mm in Extra Tele Conv video mode. Wildlife cinematography anyone?
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How is the focal length of the lens being changed by the size of sensor or capture area? Cropping the image in the camera only gives you less data to work with in editing, which may be a good thing, but certainly doesn't change the focal length of the lens.