Gene51 wrote:
Sharpness is subjective. By this I mean that it is not measurable. You can measure with precision a lens' acuity and contrast. But there is no accurate measurement for "sharpness". This is mainly because the perception of sharpness is affected by viewing distance, subject matter, camera resolution, image magnification, and above all a person's eyesight. I am aware that DXO rates a lens with regards to "sharpness" but they are using a subjective determination, and a comparison to a "perfect" or theoretically flawless lens, and they use P-Mpix, or perceptual megapixels to rate the performance of a given lens on a given camera and how it compares to perfection, assuming that the perfect lens returns a P-Mpix number equal to the camera's mp count. So, if a lens shows 21 P-Mpix on a 24mp body, it is telling you that on that body, that lens is providing 21 of 24 mp performance, or 87.5%. If another lens is tested and its P-Mpix score is 12 on the same body, then you are getting only 50% of the camera's resolution.
So, when you say something like "Zeis [sic] 24 to 70 or is it 24 to 80 2.8 is the sharpest all purpose lens available" what exactly are you referring to as sharpness?
Sharpness is subjective. By this I mean that it is... (
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👍👍👍. There are many, many superb lenses - there is no such thing as one lens sharpest for all purposes and on all camera bodies.