新35 1.8g FX 或 老35 f/2d ? (機身D800)

這篇提到
http://www.kenrockwell.com/nikon/35mm-f18-fx.htm


(1)
"35/2 AF-D is optically almost as sharp as the 35/1.8 FX wide-open, and with less distortion than any of the other lenses.
This f/2 lens isn't quite as sharp in the far corners, but it has much less color fringing than the f/1.8 lens."

35/2 AF-D光圈全開跟35/1.8 FX光圈全開差不多利(但35/2 AF-D邊緣較不利)，35/2 AF-D較35/1.8 FX少變形與紫邊

(2)
"I'd never see significant difference in actual shooting between them. If I got out my microscope,
the AF-D lens is less contrasty at f/2 than the 35/1.8G FX is at f/2, and the 1.8 G FX lens is slightly sharper at microscopic levels than this 35/2 AF-D
in the corners — but the f/1.8 lens has more obvious color fringes in the far corners of FX than the AF-D lens."

在光圈f/2時，要很用力很用力看才看出在中央及邊緣部分35/1.8 FX比35/2 AF-D利一點點

(3)
"As compared on a D800E, AF speed of the 35/2 AF-D is as fast as the AF of the 35/1.8 FX."
對焦速度在D800上一樣

我的考量是在室內使用時的
1.對焦速度 (要拍小小孩)
2.可用光圈 (如果像這篇說的光圈全開差不多利的話，好像1.8g沒太大優勢)
3.輕便性 (所以第一不考慮Sigma 35 1.4)

35 1.8g FX 跟 35 f/2d 兩隻價錢差了快一倍

不知各位大大覺得有沒有必要買35 1.8g FX呢?

感謝解惑^^