[Jacobsiu]

各位 c 兄, 請問如果系支 55 - 250mm 鏡到加支 extension tube ，會增加多小遠攝距？有無多 50 mm - 100 mm 咁多架？同邊個品牌好，我 body 系 450D. 唔該指導下，謝

[Obi-Wan]

55 - 250mm 加 extension tube, only for macro

if u want to buy a teleconverter 1.4X or 2X, use it on fix focal length lens or expensive zoom (e.g. little white), don't use it on cheap zoom, otherwise u cannot use autofocus.

if u want to take enlarged view of a distant object, buy a longer focal length lens instead. Of course very very expensive to buy 384, 484 etc.

[iso_ray]

買支副廠70-300mm 好過你咁加落去, 就算canon75-300都係1仟蚊度, 平過你買原廠Extender, 加落去真係超級哂氣, 仲要無AF

[hkdnken]

買支canon75-300 IS USM 都係4200度,

[Obi-Wan]

canon75-300IS ($4000) is one of the worst lens made by CANON, better buy 55 - 250mm IS

[kenshinkanon]

好似唔係枝枝鏡都可以加原廠Extender，最好去canon個網check下先!

[alvinkcyau]

加extender會同時限制最大光值, 如果一支f/2.8 嘅lens 加個2x 嘅extender, 支lens會變成f/5.6. 所以如果支鏡本身光圈細, 就算用得extender都唔好用.

同意iso_ray兄的說法, 買支副廠tele好過.

[deniscat]

小小白IS加Extension Tube 又ok唔ok?
1.4x ok?
2x 又ok嗎?

[Jacobsiu]

副廠咁唔知買 sigma 好 or Tam..好，仲有，系 wing shing 有無得好介紹？唔該！

[alvinkcyau]

回應deniscat:
小小白IS 加1.4X, 最大光圈得番F/5.6, 2X就得番F/8
仲可能用唔到AF

[pongyee]

F8 用唔到AF

[kwokcho]

EFS55-250mm加上延伸管EF12最大放大倍率0.28-0.05X, 加上延伸管EF25最大放大倍率0.48-0.11X

我用緊Canon Edxpender EF 2X II for 70-200mm F4 /100-200mm,F4-5.6度, 物非所值, 細光圈, 無AF, over$2000....我而家等年尾有錢買支600mm,果2000幾銀幫補下好過., 後悔................... 你已經用緊450D, 250mm都有375mm啦, 買支副廠350mm...打雀都得啦...

[kwokcho]

Sorry, it shall been "100-400mm,F4-5.6"