LEICA SUMMILUX-M 35mm f/1.4 ASPH. 11883(11874) 修復後膠合鏡組脫膠 膠合面霉蝕痕拋光 Fixing Element Separation and Cemented Surface Fungus Etching Polishing

LEICA SUMMILUX-M 35mm f/1.4 ASPH. 11874這款鏡頭有兩個常見的鏡片問題，一是後膠合鏡組會有脫膠離膠的問題，二是此膠合鏡組的兩枚鏡片的黏合面 在脫膠離膠的狀態下，常常會看到有黴菌的生長，大部分是點狀或是絲狀的霉，如果這些霉在這黏合面中長得夠久，就很可能會在其中一個黏合的鏡面上留下霉蝕痕。霉蝕痕是鏡片上永久性的傷痕，沒辦法單純透過清潔的方式去除，唯一的方法就是對這個有霉蝕痕的鏡片進行精準的拋光，拋光之後重新黏合，才有辦法讓這個膠合鏡組恢復乾淨通透。 在有霉蝕痕的狀態下，如果不先拋光，只單純的把兩枚鏡片分開、清潔之後就直接再重新黏合，霉蝕痕就會夾在兩枚鏡片中間。
LEICA SUMMILUX-M 35mm f/1.4 ASPH.有三個版本，分別是一般的黑色版11874、銀色版11883 以及鈦板11859，它們都有出現上述問題的可能性。我也曾處理過幾支FLE I 11663有相同的問題，推測non-FLE和FLE I除了光學結構相同之外，用來黏合膠合鏡組的光學膠也是一樣的，目前11663的案例比較少，可能是它們都還年輕，發病的時間還沒到，也許過幾年後就會慢慢出現相同的問題，甚至FLE II 11726/11727在十年後 可能也會有相同的問題 
這款鏡頭的後膠合鏡組，如果只是單純的脫膠離膠，就只需要按照標準的處理程序，將兩枚原本黏合在一起的鏡片分開、徹底清潔乾淨之後，便可重新黏合
如果有上述在膠合面有的霉蝕痕的問題，就必須在處理脫膠離膠的程序當中，安插一個拋光的程序，就如同這個案例一樣，在拋光完成之後，才能將兩枚鏡片重新黏合，這樣才能確保鏡片是乾淨通透的。
膠合面的拋光是需要絕對的精細準確，才能確保與原始鏡頭有一致的畫質表現。 如果有不平均或是不正確的拋光，最後兩枚鏡片是無法完美的黏合在一起的，當然 畫質也會受影響 
這個案例的後膠合鏡組，就是因為其中一枚鏡片的膠合面有明顯的霉蝕痕，所以接受了 一個膠合面的拋光 以及 脫膠離膠重新黏合兩個部分的特殊處理，從最後一張照片可以看到，處理完成之後，鏡片恢復了乾淨通透的狀態，是一次完美的修復！！ 

The LEICA SUMMILUX-M 35mm f/1.4 ASPH. (11874) commonly suffers from two main optical issues: elements separation in the rear doublet, and fungus growth between the cemented surfaces of these two cemented lenses while in a delaminated state. This fungus typically appears as spots or thread-like structures. If left long enough, it often leaves fungus etching on one of the inner cemented surfaces. Fungus etching is permanent surface damage that cannot be removed by simple cleaning; the only solution is precision polishing of the etched glass surface prior to re-cementing to allow the cemented doublet to regain its crystal-clear transparency. If you separate, clean, and re-cement the two elements without polishing out the fungal etching first, those marks will remain permanently between the elements. 

The standard Black 11874, Silver 11883, and Titanium 11859 versions of the LEICA SUMMILUX-M 35mm f/1.4 ASPH. all share the potential for this issue. I have also repaired several units of the FLE I (11663) with the exact same problem. Since the non-FLE and FLE I share the same optical design, it is likely they use the same optical adhesive for their cemented doublets. We see fewer 11663 cases right now simply because they are newer and haven't hit that age threshold yet, but we will likely see more cases emerge in a few years, and it is even possible that the FLE II (11726 / 11727) might face the same issue ten years down the road. 

If the rear doublet only suffers from separation without etching, it simply follows a standard protocol: safely separate the two joined elements, thoroughly clean them, and re-cement them. However, when fungal etching is present on the cemented surface, a precision polishing step must be inserted into the process before the elements can be re-cemented to ensure the lens is clear and transparent. Polishing a lens cemented surface requires absolute  accuracy to preserve original optical performance, as any uneven or incorrect polishing will prevent the two glass elements from mating perfectly and degrade image quality. 

In this case, one of the cemented surfaces of the rear doublet had severe fungal etching, so it underwent a specialized treatment combining surface polishing with re-cementing. As you can see from the attached photos, the doublet have fully recovered their original clarity and transparency—a perfect restoration!