Photodo was redesigned several times during their history. It looks like some of their MTF data got lost. If there is no MTF data found at the current version, I might have them in the archives. Drop me a line, if needed.
Fred Miranda Ratings rarely make a difference between several versions of a lens, like e.g. Sigma EX and EX DG versions. The ratings also may change over time and they are highly subjective user ratings only. For those and other reasons related to handling link maintenance I finally decided to remove most of their references from the main listings, as long as any other qualified review or test reference is available. Traces may be found in the print versions for each lens, but I might as well remove these to prevent overcrowding.
Last but not least the most important bits about understanding tests and reviews:
*If you did read all of the above, here's a good joke for you: "Distortion tested on the Rebel XTi was amazingly well controlled, as measured by DxO Analyzer 2 tests, with Visible barrel distortion at 28mm (0.35%), and Slight pincushioning at 70mm (0.12%), 200mm (0.11%), and 300mm (also 0.11%). To compare, in 2002 a Tamron 28-300mm showed distortion in the Very Visible range (1.40-2.73%) at four focal lengths." [source]
(Hint: They are talking about a full-frame lens - the Tammy 28-300 XR Di VC, which they seriously tested for barrel distortion (and I hope it's been just that, though I'd bet it was not ...) mounted to a Canon XTi, which is a crop sensor camera and thus only uses the center portion of the Tammy's optical formula.
If they did properly test the former lens in 2002 (I think they are referring to the 28-300 XR LD AD) using a full-frame body, the huge difference in barrel distortion is no big surprise here.)
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