[warrenwhlam]

I want to buy a lens for my new Canon 400d, my choice are:
Sigma 17-70mm f2.8-4.5 DC Macro
Sigma 18-200mm f3.5-6.3 EX DC

Which one is better in terms of daily use and for trips?
can both support 400d and support auto focus?
I already have a Canon 75-300mm f4-5.6

Please help. Thank you

[A.T.]

既然有 75-300mm，
咁當然go for Sigma 17-70mm f2.8-4.5 DC Macro la~

[chun0559]

一來你已經有75-300 ，我認為無需要重覆再買類似既距離。
加上17-70 成像會比18-200好 ，又有1:2 既Marco ，
所以我建議買17-70 比較好.
*不過有一點要留意 ， 佢既F2.8 只在17-21 mm 先有

[warrenwhlam]

Thank you for your help. I think i will go for Sigma 17-70mm
Just a few more questions.
Does it support auto focus when use with 400D?
And how is the focus speed?
Chun0559: F2.8 只在17-21 mm 先有, then after 21mm, what is the largest aperture value?
Approx. how much? and where can i buy it at best price?

Thank you for your help again

[彼德班]

Zoom 盡至 70mm 最大光圈值 f/4.5

價錢大約 $2,700 ~ $2,800

[彼德班]

400D 用此鏡當然有 AF (記得買時講明要 Canon EF Mount 或最好帶埋部機去試)

自動對焦速度一般啦.