Further readings for the Canon EF-S 17-55mm f/2.8 IS USM
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Introduced alongside the firm’s new top-of-the-range OM-D E-M1 model, this new pro-grade standard zoom is the long awaited rival to Panasonic’s constant aperture G X Vario 12-35mm f2.8 ASPH model. Read on to find out how well it performs.
After the runaway success of the full-frame 35mm f/1.4, Sigma is taking the initiative with this new ultra-high speed, pro-level standard zoom designed for APS-C format cameras. The specification is particularly promising, but does it mean the end of fixed focal lenses for APS-C? Read on to see how well this cutting-edge model performs in our labs.
For many people an introduction to photography is through a compact camera: usually, these days, one with a zoom lens covering medium-wide through to short telephoto. The next step is often an SLR and the “standard” zoom, covering the same range. The quality of this “standard” zoom can be the difference between great results and disappointment, so the choice is important. This Sigma 17-70 f2.8-70 f2.8-4 DC Macro OS HSM C Canon is both good and versatile, no disappointment here.
I'm an owner of EF-S 17-55 F2.8 IS USM and 70D. I'm disappointed at the results shown here, because EF-S 17-55 F2.8 IS USM is the only flagship zoom lens for APS-C DSLR and some of the other reviews have given it quite a credit as being comparable to the full-frame 24-70 F2.8 L II in optical performance.
Could it be that the poor result is due to "focal point shift", a common issue seen by many Canon lens. For example, my own EF-S 17-55 F2.8 IS USM needs a "plus 4" micro focus shift adjusted in 70D to achieve the best focusing.
Thanks for your feedback, it is very important because it enable us to improve/check our measurements. In this specific case, we did many test on different samples to check our results.
About focusing micro adjustment, the DxOMark protocol is made to avoid such trouble: For each couple focal-aperture measured, we perform what we call a “through focus”: We shot around 40 pictures with short move on an optical rail between each picture. We measure sharpness on each picture and we performed all measurement on the best one. This best one correspond to the best focusing position.