[mickey9801]

想買支遠攝鏡，因為間唔中都會郊遊打下雀，本來想買支大白，不過太笨重好難經常帶出街，想問下各位ching如果用小白+2x，實際效果OK嗎？

[Obi-Wan]

我以前用大白，現用愛死小白加1.4 同2X
對焦用50D唔大慢，畫質F8後中央ok, 但冇大白Sharp

[mickey9801]

Obi-Wan:
用咗1.4x或2x會令對焦變慢的嗎？因為我也有興趣試下影運動，影雀時也愛連拍飛翔的雀。小白+2x會有影響嗎？小弟的機是7D

[h0001244]

After adding 2X, surely reduced the focus speed as there are less light entering the lens due to reduced F-stop by 2 step.....
If you try putting 2X on Tamron 18-200 3.5-6.3 lens, you can't even focus on under bright sunlight

[kwmsn]

300 /4加1.4X
100-400加1.4X
用5d2重有無自動對焦?

[hungkeec]

EF 100-400加1.4X
用5d2無自動對焦
ok
1Ds III 有自動對焦

[Obi-Wan]

如果要追飛鳥，小白加1.4鄀還可以，但加2X慢dd， 多數要好彩先影到，但打蝶冋蟲冇問題

[mickey9801]

看了各位ching的意見看來真可以考慮用小白+1.4x，接下來就要考慮價錢問題。雖然3月會出新小白，不過經常聽說Canon又要加價，如果等到3月先至看價錢決定買新小白還是舊小白，真怕到時連舊小白都會加埋價。現在舊小白供機價都要HK$14xxx，已有點吃力了。

[homankop]

小白+大白

[manuel629]

小白+2x still have auto focus? what kinds of performance will degrade?

[manuel629]

小小白+2x still have auto focus? what kinds of performance will degrade?

[Frankyma]

小小白+2x still have auto focus?

失去AF功能, 手動對焦有點困難, 要用手指尾拎個對焦環, 如習慣都算OK

[Obi-Wan]

小小白+2x still have auto focus?

With AF in 1 series
http://en.wikipedia.org/wiki/Canon_Extender_EF

[manuel629]

多謝CHING.