elfwong wrote:
有個疑問變焦鏡與定...(恕刪)
DXOMARK的解像力測試是結果論，是實拍圖再來數毛，所以結構，像素大小，畫幅大小等總總影響都不會改變它數毛的這件事，因此：
1. DXOMARK的測試方法，鏡頭解像力都是向最高畫素的感光元件靠攏，真的要細究你只能說CANON 的5Ds R在DXOMARK測試是踢了鐵板，任何人都知道他沒多測NIKON D850配鏡頭是最可惜的地方。少了這一塊拼圖，確實沒那麼好玩。 就如同CANON 400mm f2.8 L在 5DsR的測試，這隻SONY100-400mm GM 在A7RII測試是同樣36 p-mix，並沒有強過它。和NIKON的400mm f2.4 FL比，沒有人知道，我可以猜NIKON會贏的，不過，DXOMARK 目前沒這個數據，而且這並不影響變焦鏡銳利度能贏過定焦大砲的結論啊。
2.根據下面的敘述，DXOMARK並不是取最高銳利度的焦段代表，而是取加權平均。因此你的顧慮是被考慮過的。
The DxOMark Lens Score corresponds to an average of the optimal quantity of information that the camera can capture for each focal length.The quantity of information is calculated for each focal length/aperture combination and the highest values for each focal length are weighted to compute the score.
再來該站原始對 100-400mm GM的測試有提到，300mm 時較低，400mm 時又提高，而且中心到邊界的解像力幾乎沒有降低。看了它的焦段測試圖，沒有你說的 100-400mm 拉到400mm 的sharpness分數有明顯下降。
While the new Sony is sharp wide-open across the central 20% of the frame, dropping a little in the mid and outer zones, that’s at 100mm, where you would expect a tele-zoom lens like this to perform well. At 300mm, image sharpness is very good centrally, but sharpness drops somewhat towards the outer zone, though it’s still good for a tele-zoom. What is surprising, however, is that Sony somehow has managed to improve on sharpness at 400mm. While it’s not any sharper centrally, it has more uniform sharpness across the frame than at 300mm, with the outer zones at a similar level to the center. As no one buys a lens like this to use at mid-focal lengths only, that’s pretty impressive.
