[M42] Pentax Super-Multi-Coated Takumar 50mm f1.4

鏡頭資料》http://m42.artlimited.net/lens_detail.php?lid=12
對焦距離：0.45m - 無窮遠
光圈：f1.4 – f16
口徑：49mm
重量：230g
鏡片結構：七片
光圈葉片：八片 
出產年份：1971

備註：The bad news: unfortunately, both versions, and the SMC Pentax 50/1.4
with 52mm filter ring, have an internal element made of material known as "hot glass"
which turns yellowish to brownish with age.  The affected lens element contains
thorium, a radioactive rare earth element. Several lens makers including
Pentax, Kodak, Leica, and Canon used this manufacturing technique in the
1940s to early 1960s to lower the index of refraction of specific lens elements. 
The yellowing is curable by exposure to ultraviolet or sunlight, as has been 
discussed on the Spotmatic Yahoo! Group.The earlier 8-element 50/1.4
Super-Takumar and the various 55/1.8, 55/2.0 and 55/1.9 Takumars do
not turn yellow, nor do the newer 50/1.4 SMC Pentax-M/A/F/FA.

上面是提到，此鏡還有口徑為 52mm SMC 50mm f1.4，由於使用了叫做”釷”的放射性稀土元素 (長輩們說是鑭系玻璃)，所以會因為時間久遠而變黃，這個黃是可以治療的，用紫外線或日光照照就好了(有網友說白色 LED 燈也可以)！從日本標回來的時候有詢問這個問題，不過賣家沒有很確定，我也不太會看，想說先標回來研究研究！

Pentax 早期 M42 單鍍，鏡片結構為 8 片的 Super-Takumar 50mm f1.4 以及後期進入 K 接環以後的 M/A/F/FA 50mm f1.4，另外同為標頭的 55mm 系列 (f1.8, f2.0, f.19)則沒有黃化的問題。(我個人倒是沒找到過有 55mm f1.9 這一顆)

實拍照》

Praktica MTL50 + Pentax Super-Multi-Coated Takumar 50mm f1.4

Pentax K10D + Pentax Super-Multi-Coated Takumar 50mm f1.4

Pentax Spotmatic F + Pentax Super-Multi-Coated Takumar 50mm f1.4

Sony A450 + Pentax Super-Multi-Coated Takumar 50mm f1.4

Pentax ME Super + Pentax Super-Multi-Coated Takumar 50mm f1.4 + Konica 100

Pentax ME Super + Pentax Super-Multi-Coated Takumar 50mm f1.4 + Fujifilm X-tra 400

本鏡實拍照片集：Pentax S-M-C Takumar 50mm f1.4
鏡身照》