Sigma鏡頭一問

邊支好視乎你主要影甚麼.
兩支都係影運動一類需要快速對焦及高速快門的好鏡頭
講長係120-300mm f2.8長些小,有時真係差些小就差些小.但係佢會貴好多同埋好重下.就算光線夠手持都唔頂得幾耐.通常要配單腳架先掂
而70-200mm f2.8就係一支比較機動性高的鏡頭,光線夠的話可以長期手持都OK.但焦距就短小小.
至於你話加2X conventor就唔係好建議.Zoom鏡最多加1.4X好喇,加到2X一來最大光圈得翻f5.6,嚴重影響對焦速度同埋入光量,失去咗買大光圈鏡頭的意義,而且畫質會鬆散好多.如果要求高分分鐘1.4X你都未必接受得到.高質定焦鏡勉強可以加2X,不過都係可免則免.
如果真係要長不如買一支長焦鏡例如Sigma 80-400mm OS或者Tamron 200-500mm.雖然都係光圈細同對焦慢,但畫質會满意好多.以下係4支鏡的review.
70-200mm f2.8 macro
http://www.photozone.de/8Reviews/lenses/sigma_70200_28_nikon/index.htm
120-300mm f2.8
http://www.photozone.de/8Reviews/lenses/sigma_120300_28/index.htm
Sigma 80-400mm OS
http://www.photozone.de/8Reviews/lenses/sigma_80400_4556os/index.htm
Tamron 200-500mm
http://www.photozone.de/8Reviews/lenses/tamron_200500_563/index.htm