[天下無敵]

想買多支鏡頭．唔知買咩鏡頭好．

又想一鏡走天崖，唔使下下換來換去甘煩．

我部係３５０Ｄ呀

[Round]

An interesting reason behind a common question.

IMO, getting a DSLR is mainly because it provides the flexibility of using different lenses for different situations. You don't want to swap lenses but you go to buy a DSLR.

Going back to your questions, it depends on what sort of situation and what type of pictures you mostly take. People will suggest you Sigma 18-200.