Canon's EF 70-200mm f/2.8L USM zoom lens was used more often for this field-test with the Extender EF 1.4x although some of the images presented here were actually shot at locations during actual photo assignments. The effective focal lengths will become 98-280mm. Nevertheless, in this page are some examples of how the zoom lens' focal lengths of 70 to 200mm have changed after been fitted with the Extender EF 1.4x. The first batch of the images shown here was shot with the zoom lens alone and the second was with the EF 1.4x attached. Canon EF 70-200mm f/2.8L USM without EF 1.4x At 70mm At 100mm     At 135mm At 200mm Compare the above four images with those below and you will see that the enhanced 70mm focal length (below) looks similar to the prime 100mm's (above) angle-of-view. The same goes for the enhanced 100mm with the 135mm from the first batch. And the enhanced 135mm looks very similar to that of the 200mm's angle-of-view. Well, there is not a 280mm prime lens to compare with the enhanced 200mm focal length because Canon does not have such a focal length in its EF lenses' lineup. Canon EF 70-200mm f/2.8L USM with EF 1.4x attached At 70mm (98mm) At 100mm (140mm)     At 135mm (189mm) At 200mm (280mm) Just like the EF 2x, Canon recommends that when the EF 70-200mm f/2.8L USM zoom lens is fitted with the EF 1.4x and mounted on EOS cameras having multi AF points, only the center autofocus point should be used. Of course, many EOS users have been using this zoom lens with all AF points activated when fitted with either Extenders and find all of them to be working. Well, it is a mere recommendation, not a warning of any sort for having all the AF points active. When the EF 1.4x is used with the EF 100-400mm f/4.5-5.6L IS USM zoom lens, only the center AF points of both the EOS-3 and EOS-1V cameras can be used for autofocus. The EF 1.4x is usable with all single focal lengths EF lenses of 135mm (except for EF 135mm f/2.8 Soft Focus) and longer, as well as L-series zoom lenses like the EF 70-200mm f/4L USM, EF 70-200mm f/2.8L USM and EF 100-400mm f/4.5-5.6L IS USM except for the EF 35-350mm f/3.5-5.6L USM. It has an overall length of 27.3mm and a dry weight of only 200 grams. The internal construction is composed of 5 elements in 4 groups. << Back to Main . 1 . 2 . 3 .