Canon EF 70-300mm f/4.5-5.6 USM DO IS - Full Format Review / Test Report
Lens Reviews -
Canon EOS (Full Format)
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Review by Klaus Schroiff, published August 2010
The Canon EF 70-300mm f/4.5-5.6 USM DO IS is a unique lens in its class. This is not all that obvious from its naked specifications but because of its DO design. DO refers to a multi-layer Diffractive Optical element that bends light steeper than conventional (refractive) elements thus allowing a shorter design in conjunction with less color fringing and less spherical aberrations.
It is the second Canon EF lens to use this technology with the first one being the Canon EF 400mm f/4 USM DO IS. The DO lenses are an own group within the Canon lens hierarchy - they are distinguishable via a green ring at the lens front rather than e.g. the red one used for L class lenses. The DO element is also visually recognizable (unlike UD or CaF2 elements). You may notice the concentric circles in one of the glass elements in the following image.
The lens has a rather conventional mechanical design - it extends towards the long end of the zoom range. Size-wise it is a fat lens (large diameter) but very short (28% shorter according to Canon) for such a tele photo lens. At 720g it isn't especially light weight but the pretty good build quality, located somewhere between Canon consumer grade and L class lenses, takes its toll here. A negative side effect of the additional weight the zoom mechanism is a rather strong tendency to creep when tilting the lens up- or downwards. Canon has integrated a zoom locking switch but unfortunately this works in the 70mm position only.
Thanks to a ring-type USM drive the AF speed is very fast and basically silent. FTM (full-time manual focusing) is always possible in one-shot AF mode. Unlike most consumer grade lenses the EF 70-300mm f/4.5-5.6 DO USM IS has a non-rotating front element.
One key selling factor for this lens is naturally the Image Stabilizer (IS). Camera motion is detected by 2 gyro sensors which measure the angle and speed of the shake. This information is used to shift a lens group off the optical axis (basically a forced decentering) to counteract this motion.
The result is a significant improvement of "handholdibility" (3 f-stops equivalent). The IS of the EF 70-300mm DO offers 2 different modes: mode (1) for static scenes where the IS corrects shake both vertically as well as horizontally
mode (2) for action photography (object tracking) where only vertical shake is corrected
Please note that IS has its limitations - you may be able to shoot at much slower shutter speeds but slow shutter speeds come at risk of motion blurr (of fast moving objects in your scene). That said IS is immensely useful in many field situations.
Here's a comparison with its nearest cousin - the EF 70-300mm f/4-5.6 USM IS.
EF 70-300mm f/4.5-5.6
USM DO IS
EF 70-300mm f/4-5.6
||18 elements in 12 groups, 1x DO element
||15 elements in 10 groups, 1x UD element
|image stabilizer efficiency:
||3 f-stops, 2 modes
||3 f-stops, 2 modes
||ring-type USM with FTM and non-rotating front element
||micro-USM, no FTM, rotating front element
|approx price tag: