CANON FD 300mm f/4.0 L 光圈葉片沾油光圈無法縮放光圈葉片除油清潔 Aperture malfunction because of oil on the blades

這支 CANON FD 300mm f/4.0 L 的光圈故障，轉動光圈環的時候，葉片不會收縮，一直都是呈現做大的狀態。這問題的成因是 光圈葉片有油漬，油漬沾黏了葉片阻礙了這類有連動光圈功能的鏡頭的葉片無法收縮，只會呈現光圈全開的狀態。

將整個光圈組件徹底清潔乾淨，便能將問題解決！

This CANON FD 300mm f/4.0 L had an aperture malfunction because of oil on the aperture blades.
For a lens incorporated the auto-diaphragm, the oil on the blades is the main reason that makes the aperture blades unable to work (close) properly while turning the aperture ring.
The function can be totally restored by making a thorough cleaning on the aperture blades and related parts.