Nevertheless, the EF 100-400mm f/4.5-5.6L IS USM zoom lens is still a good buy for those who are thinking of investing in one. To give an idea of how the image magnification is like with the lens' eight different focal lengths (yes, eight), here are the comparison shots of the Kuala Lumpur Tower. At 100mm At 135mm At 150mm At 200mm At 250mm At 300mm At 350mm At 400mm The EF 100-400mm f/4.5-5.6L IS USM lens has angle-of-views of 20-degree and 5.10-degree at the 100mm and 400mm settings respectively. The lens' construction is composed of 17 elements divided into 14 groups while its aperture consists 8 blades. The minimum aperture is f/32 (at 100mm) and f/38 (at 400mm). However, for EOS-3, EOS-1, EOS-1N and EOS-1N RS users, the minimum aperture may be slightly different since these cameras use 1/3-step in their exposure settings. Back to the idea of investing in this lens. For those who already have the EF 35-350mm f/3.5-5.6L USM 10x zoom lens, I don't think it is necessary for them to invest in the EF 100-400mm IS. If you already have the discontinued EF 80-200mm f/2.8L AFD zoom, it is okay to have this one. With its debut, the EF 100-400mm IS lens has also replaced the older EF 100-300mm f/5.6L AFD zoom. If you already have the EF 300mm f/4L IS USM telephoto, is it worthwhile to invest in the EF 100-400mm f/4.5-5.6L IS USM lens. That also depends on what you are shooting. A friend of mine has both the EF 300 and EF 100-400 IS lenses since shooting motorsports and 4x4 expeditions are his specialties. As for me, I find my EF 70-200mm f/2.8L USM (I have it as well) to be more flexible with the types of work that I do. Since I am saving to buy the EF 500mm f/4L IS USM telephoto lens, there is no need to invest in the EF 100-400mm IS version. Text and photos by Philip Chong. Copyright 1999 by Canon Marketing (M) Sdn Bhd. << Back to Main . 1 . 2 . 3 . 4 . 5 .