Confused about FF lenses on cropped sensor (Sigma 35mm 1.4)

Started Oct 16, 2013 | Discussions thread
esbn New Member • Posts: 8
Re: Confused about FF lenses on cropped sensor (Sigma 35mm 1.4)

OK so I went and looked at and you must have found the two Nikon / Sigma AF 35mm f/1.4 DG HSM | A lens analysis reports.

The D3X has a pixelsize of 0.00595mm and the D7000 0.00478mm. But the D3X has 24mp and the D7000 only 16.7

"Further, larger pixels receive a greater flux of photons during a given exposure time (at the same f-stop), so their light signal is much stronger. For a given amount of background noise, this produces a higher signal to noise ratio — and thus a smoother looking photo.

This is not always the case however, because the amount of background noise also depends on sensor manufacturing process and how efficiently the camera extracts tonal information from each pixel (without introducing additional noise).

In general though, the above trend holds true. Another aspect to consider is that even if two sensors have the same apparent noise when viewed at 100%, the sensor with the higher pixel count will produce a cleaner looking final print. This is because the noise gets enlarged less for the higher pixel count sensor (for a given print size), therefore this noise has a higher frequency and thus appears finer grained." Cambridge in Colour

I still find it curious that the corner performance is that exaggerated from FF to APS-C. Although I could think that the 0.00595 to 0.00478 ratio somehow manifests as a resolution degradation ratio that translates to the difference seen . Or it could be that the lens has a circle of less resolution that falls between the measured areas on the FF but also falls in thecorner measurement area on the APS-C

In summary I am curious too - And if somehow a knowledgeable person could write up a summery for dummies on

The MTF for the Sigma 35mm 1.4

If you go back and compare the 5D D3X and D7000 and compare to the MTF you will see that the fall in resolution is fallen to the lowest within the APS-C area. So the only discrepancy is that the center sharpness is lower on the D3X than the others. I hope this helped though I am not sure : ) my head is slightly spinning now and I have 60 Tabs open in safari and I spent a while writing this and researching so it is gonna get posted anyways : )

I for one would read and be happy

 esbn's gear list:esbn's gear list
Pentax K-5 Sigma 10-20mm F4-5.6 EX DC HSM Sigma 24-70mm F2.8 EX DG Macro Sigma 85mm F1.4 EX DG HSM +1 more
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