The EF 135mm f/2.0L USM is the other 135mm lens that can be used with the EF 1.4x, turning it into 189mm f/4 telephoto. The EF 1.4x reduces by a full stop the effective maximum aperture of any prime lens it is attached to. The following two photos below were shot with this lens, with and without the Extender EF 1.4x attached. EF 135mm f/2.0L USM With the EF 1.4x (189mm)     EF 180mm f/3.5L Macro USM With the EF 1.4x (252mm) When I was testing the EF 180mm f/3.5L Macro USM for issue No: 45, the camera used was the EOS-1N RS, which made it impossible to have any AF operation when the EF 2x (equivalent to a 252mm f/6.3 lens) was used with it since only both the EOS-3 and EOS-1V models were able to autofocus with lenses having maximum aperture smaller than f/5.6. The above photos shown the extended angle-of-view that the 180mm Macro lens has become when the EF 1.4x was used. With any prime EF 300mm lens, the EF 1.4x will make it behave like a 420mm telephoto, which is not much when compared to what you can get from a 300mm focal length's angle-of-view. The photos of Italian 500cc rider Valentino Rossi below were captured with the EF 300mm f/2.8L IS USM lens, with and without the EF 1.4x. You can see from here the "increase" in focal length in these shots. This angle-of-view with the EF 1.4x is almost similar to what one will get with a prime 300mm lens when used with the digital EOS D30 camera, which multiplies the focal length by a factor of 1.6 times. Valentino Rossi (300mm) Valentino Rossi (420mm)     Sammi Cheng (200mm) Sammi Cheng (280mm) However, the EF 1.4x is more worth its value when it comes to using it with a lighter lens like the EF 70-200mm f/2.8L USM or EF 70-200mm f/4L USM. I did use the former zoom lens with the EF 1.4x when covering the 2000 I-concert of Hong Kong's Cantopop Queen, Sammi Cheng, at Malaysia's Genting Highlands. The difference in contrasts between the two photos has nothing to do with the zoom lens or the EF 1.4x but due to the changes in the concert lighting used, which goes from bright to subtle, dim to bright and back forth all over again. Text and photos by Philip Chong. Copyright 2000 by Canon Marketing (M) Sdn Bhd << Back to Main . 1 . 2 . 3 .