D600 vs d7100

Started Apr 26, 2013 | Discussions thread
noirdesir
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Re: "It is better, because image circle is larger" - enough said
In reply to ultimitsu, May 13, 2013

ultimitsu wrote:

noirdesir wrote:

ultimitsu wrote:

noirdesir wrote

Well, I don't know whether the Sigma 17-35 mm f/2.8-4 is better or worse than the Tokina 11-16 mm.

It is better, because image circle is larger the resulting image has much more detail, a native strength of being FX.

This is equivalent to saying a larger displacement engine has more power than one with less displacement when asked to compare two specific models. I should stop right here. Give them enough rope and ....

Given that the Sigma was tested on a 22 MP body and the Tokina on a 18 MP body, the resolution numbers (ie, the P-Mpix ratings) are not directly comparable. If you scale them with the ratio of number of MP (22.12/17.92 = 1.235), ie, 9 * 1.235 = 11.1, both lenses resolve the same number of 'MP' (as defined by DxO).
You can also look at more bodies where these lenses were tested on and compare how much Mpix per MP they get: Sigma on 5D 8 (12) vs. Tokina on 40D 6 (10), or Sigma on 1DsIII 9 (21) -  Tokina 7 (15). Overall, given the same amount of MP on the sensor behind both lenses, both lenses achieve about the same final resolution.
Thus, for this lens pair, your premise of bigger (image circle) = better (resolution) evidently does not apply and your statement about the Sigma having "much more detail" was not proven to be correct.

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