Canon FD 300mm f/2.8 L 救一支鏡頭！重新拋光受損傷的鏡片 Saving a lens by re-polishing a damaged lens element

客人將這支 Canon FD 300mm f/2.8 L送來的時候，它有一個內鏡片因不明原因被胡亂打磨過，造成鏡片表面非常粗糙 凹凸不平整，也讓這支鏡頭沒辦法拍出清楚的照片，不管是最大光圈或是縮到f/8.0成像都是糊糊的

我依照傳統的拋光處理，製作拋光模具之後，小心的拋光，將大部份粗糙的表面拋除，讓鏡片重新恢復它原本的曲度以及平整光滑，只留下一些比較深的點狀傷痕沒有拋除

最後四張試拍照 兩兩對比，都是全開光圈f/2.8的時候拍的，可以清楚看到 拋光前、後的成像有非常顯著的差異。這支鏡頭在拋光後的成像 全開光圈就已經是清晰銳利，我察覺不出跟正常的鏡頭有差異

透過拋光的方式，拯救了一支原本要被廢棄的鏡頭！

When the guest brought me this Canon FD 300mm f/2.8 L lens, one of the inner elements had been rough-ground for unknown reasons, resulting in a very rough and uneven surface that prevented the lens from producing clear photos. Regardless of whether shot at wide-open aperture or stopped down to f/8.0, the images were always blurry.

I followed traditional polishing methods, creating a polishing mold, and carefully polished the lens, removing most of the rough surface and restoring the original curvature and smoothness of the element, while leaving some deeper point-like scratches untouched.

In the end, I took four test shots, paired for comparison, all shot wide open at f/2.8, clearly showing a significant difference in image quality before and after polishing. The images with the lens after polishing were sharp and clear even at full aperture, and I couldn’t detect any difference compared to a normal lens.

Through the polishing process, I salvaged a lens that would have otherwise been discarded!