Further readings for the Canon EF-S 17-55mm f/2.8 IS USM
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Launched side-by-side, the EOS 760D and EOS 750D (aka T6s and T6i in North America, respectively) share a lot in common, including the same high-resolution 24.2-Mpix APS-C CMOS sensor complete with Canon’s Hybrid CMOS AF III for fast and accurate focusing. We’ve put the two models through our labs coupled with a wide range of native and third-party Canon-mount lenses. Read on to find out how these models perform.
The EOS 7D Mark II is Canon’s flagship APS-C sensor DSLR, boasting a 20Mp resolution and a host of high-end features. It’s a popular choice for many serious enthusiasts and semi-pro photographers, so we’ve tested over 300 lenses on it to help you pick out the best one for you. In this first part of a two-part review, we round up the best zoom lenses for the Canon EOS 7D Mark II.
Designed specifically for use on smaller APS-C sensor DSLRs, the new EF-S 24mm is a wide-angle pancake prime featuring Canon’s STM step autofocus motor for smooth video capture. At just $149, it looks like a “no-brainer” for Canon APS-C video shooters, but how does it compare optically against a vast range of other options available? We dissect the DxOMark Lens Metric Scores to find out.
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.
You might want to see my response on a potentially related question, at: [url=https://forum.dxomark.com/index.php/topic,5188.msg9563.html#msg9563]https://forum.dxomark.com/index.php/topic,5188.msg9563.html#msg9563[/url].
It's very difficult for any lens to achieve the same resolution on an APS-C sensor as on a full frame sensor, just a smaller area on which to focus the image. That smaller area means the tolerances in the lens must be much tighter on APS-C than on full frame to achieve the same result. I go into more detail at the link above.
This may not be the only reason for a disappointing rating, but it may help explain why you're seeing some of those differences.