二手鏡頭的價格可以比全新便宜 30–50%， 但如果不知道怎麼驗機， 便宜買到的可能是一個後續麻煩不斷的問題鏡頭。 本篇由青蘋果3C鑑定團隊整理， 把每一支鏡頭入庫前必經的完整檢查項目， 用買家看得懂的語言一次說清楚： 從光學狀況到對焦功能、從入塵判斷到移焦測試， 讓你在選購或出售二手鏡頭前， 都能做出有根據的判斷。

A second-hand lens can save you 30–50% compared to new—but without knowing how to inspect one properly, that discount can come with hidden costs. This guide from Green Apple 3C’s authentication team covers every check our specialists run before accepting any lens into inventory: optical condition, autofocus performance, dust identification, and focus shift testing—explained in practical, accessible terms for buyers and sellers alike.