Shown below are comparison photos of how the angle-of-views changed when the EF 300mm f/2.8L USM is fitted with both the Extender EF 1.4x and 2x respectively. Mick Doohan captured with EF 300mm lens alone Mick Doohan captured with EF 300mm plus Extender EF 1.4x Mick Doohan captured with EF 300mm lens alone Mick Doohan captured with EF 300mm plus Extender EF 2x Okay, now you have read about the Canon EF 300mm f/2.8L USM lens, the question remains: Should you invest in one? Or maybe the EF 300mm f/4L IS USM is a better deal? Let me make it simple for those who can't decide. If you can afford to buy one and carrying such a heavy lens around for your assignments is not a hassle at all, go get one. If you can't imagine yourself carrying this lens around for those occasions where your trusty Canon EF 80-200mm f/2.8L AFD or the EF 70-200mm f/2.8L USM zooms are simply not adequate enough for the shoot, then you better go for the lighter EF 300mm f/4L IS USM version. Oh yes, unless you are already an owner of the superb Canon EOS-3 camera, the Image Stabilizer lens' AF will not function when it is fitted with the Extender EF 2x. All other EOS cameras will automatically cancel the AF mode when the 2x extender is attached to any EF prime lens having a maximum aperture of f/4 or smaller. Text and photos by Philip Chong. Copyright 1999 by Canon Marketing (M) Sdn Bhd << Back to Main . 1 . 2 . 3 . 4 .