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The score of Tamron 70-200 f2.8 Di VC is higher than Canon 70-200mm f4L IS on an APS-C Canon Camera like the 550D. Does this make the lens better than an L Lens in terms of image quality? Autofocus?

The Perceived MPix for a Canon L lens is actually same as compared to Sigma 17-70mm 2.8-4 Lens. How is that possible and does it matter too much when buying a lens for APSC?

I would plan to use these lenses mostly in daylight - outdoor for football matches or occasional portraits (full body / headshots).

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  • \$\begingroup\$ This is pretty much the same question and answer as an existing question, the lenses are just (slightly) different. But it's all the same thing: the only thing usable at DxO Mark are the actual test numbers, not their weighted "scores" that may or may not place the same weight on various factors as the rest of us do. \$\endgroup\$
    – Michael C
    Jun 7, 2016 at 8:18
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    \$\begingroup\$ Possible duplicate of Tamron 70-200 Di VC vs Canon 70-200 II \$\endgroup\$
    – Michael C
    Jun 7, 2016 at 8:18
  • \$\begingroup\$ AF has nothing to do with image quality as it is normally defined. Most IQ tests are done using very careful manual focusing. \$\endgroup\$
    – Michael C
    Jun 7, 2016 at 8:31
  • \$\begingroup\$ link to DxO pages would be useful - some may not have seen their charts which allow very useful comparisons. \$\endgroup\$ Jun 7, 2016 at 8:45
  • \$\begingroup\$ dxomark.com/Lenses/Compare/Side-by-side/… \$\endgroup\$ Jun 7, 2016 at 8:47

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Does this make the lens better than an L Lens?

It all depends on what way you mean when you use the word "better":

  • Sharper at common apertures and focal lengths? At the center of the frame or over the entire field of view?
  • Less chromatic aberration at a particular focal length and aperture?
  • Less light falloff at a particular focal length and aperture?
  • Wider maximum aperture? (hint: that's the biggest difference in the two lenses' DxO Mark overall score)
  • Value for price?
  • Ruggedness and ability to withstand harsh environmental conditions?
  • Light and compact for hiking or long shooting session?
  • Guaranteed compatibility with future Canon camera bodies?
  • Autofocus accuracy? Autofocus speed? Autofocus frame-to-frame consistency?

As is often the case with comparisons between two zoom lenses, one might perform better at certain focal lengths and apertures and the other will perform better at other focal lengths and apertures. One might perform better in terms of chromatic aberration, the other may do better with regard to light falloff in the corners. One might give better image quality when carefully focused manually (as all tests at DxO Mark are conducted), the other may give better AF performance when tracking moving subjects.

There's no simple way to define which lens is "better" than another. On order to decide which lens is "better" for a particular use case, the requirements of that use case must be considered and applied to the performance of each lens.

In the case of the two lenses in question used for sports/action in daylight conditions the superior AF performance of the Canon 70-200mm f/4 IS is probably a larger consideration than the slightly better optical performance (as measured by DxO Mark) of the Tamron SP 70-200mm f/2.8 Di VC. The comparison of the same two lenses at The-Digital-Picture is a much more mixed bag, with the Canon sharper in the corners across the focal length range and even in the center at 200mm and f/4 than the Tamron. The Tamron has a reputation for less than stellar AF performance when use on moving subjects.

On the other hand, for portraits and concerts the larger f/2.8 aperture of the Tamron is probably the largest differentiator between the two. Especially when used with an APS-C camera that limits the low light performance of the smaller sensor.

P.S. - Someone please explain to me how that is a 13 P-MPix vs. 9 P-MPix score at DxO Mark based on their own measurements? enter image description here

The same comparison (200mm @ f/4) at The-Digital-Picture.

Please keep in mind that most online testing sites test a single copy of a particular lens model. Copy-to-copy variation between one example of a specific lens model and another example of the same model can, and often does, vary as much or more than differences between comparing a single copy of lens X and a single copy of lens Y when both lenses have similar focal lengths, maximum apertures, and build quality.

Roger Cicala, founder and chief lens guru at lensrentals.com, rarely publishes test results of lenses unless he has tested and averaged the results from a minimum of ten samples of a particular lens. But Roger tends to only measure MTF, or "sharpness", at various points in the lens' field of view. He doesn't measure other things such as geometric distortion, peripheral light falloff, out-of-focus rendering (bokeh), etc. He's published more than a few blog entries regarding copy-to-copy variation between "identical" lenses.

Measuring Lens Variance
Fun with Field of Focus II: Copy-to-Copy Variation and Lens Testing
Things You Didn’t Want to Know About Zoom Lenses

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  • \$\begingroup\$ Thanks that sums it, now down to weight. I will physically check the weights on my Camera and decide if I can take the Tamron I would go with Tamron. \$\endgroup\$ Jun 7, 2016 at 10:27
  • \$\begingroup\$ Just be advised, the AF of the Tamron may not be up to the task of sports/action. \$\endgroup\$
    – Michael C
    Jun 7, 2016 at 11:26
  • \$\begingroup\$ Thanks, I will keep that in mind. I appreciate the effort you put in your answers. \$\endgroup\$ Jun 8, 2016 at 1:30

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