Tested with a Canon EOS 20D

continued

Optically the Canon 70-300 f4-5.6 IS USM hasn’t done as well as I had expected in the Canon EOS 5D test. Real world results have been fine, but optical tests are a bit of a mixed bag. One reason for that may be that Canon’s biggest market for this lens will be with Canon Digital Rebel / 350D/ 400D/ 10D/ 20D/ 30D smaller sensor cameras, so in marketing terms it makes sense to optimise this lens for these cameras. Having compared the two sets of tests so far it looks like that’s exactly what Canon have done. Results with the Canon 20D are the best I’ve seen from a 70-300 zoom with some drop in sharpness in the corners at full aperture and a tiny amount of CA - purple fringing - on certain subjects - far less than with the Canon EOS 5D, but very good central sharpness at almost all settings and by f8 overall results are excellent.

Apart from making looking through the viewfinder slightly disorientating, Canon claim a 3 stop increase in steadiness with the IS system on this lens. In practice, it depends a bit on what you’re prepared to accept as sharp. If you only make small 6x4 inch / 15x10cm prints then 3 stops is probably about right, but if like me you judge sharp to mean pin sharp, then the gain is about 2 stops. However, if there’s one type of lens that really gets the most benefit from an IS system, it’s a slightly slow tele zoom like this. So if I could only have one stabilised Canon lens in my bag it would be this one.

All 70-300 zooms are compromises, usually with poor performance in one area or another. If you use a Canon DSLR camera with the smaller APS-C sized sensor - in other words any Canon DSLR except the Canon EOS 5D or 1Ds - this lens is made for you. For Digital Rebel or 10D/20D/30D users, this lens, on optical terms alone, is the best 70-300 I’ve used, and that’s before you take the Image Stabilisation into account.

Full Test Coming Soon