This Zeiss-Opton Biogon 35mm f/2.8 T (Contax RF mount) is a lens I added to my collection over twenty years ago, back when I was still actively shooting film. Its defining feature is the highly protruding rear element, which comes very close to the film plane. This design was intended to achieve near-zero distortion, resulting in images with virtually no geometric deformation and extremely high resolution. However, what was an advantage in the film era becomes a limitation in the digital age. Because the rear element sits extremely close to the image sensor—and digital sensors are less capable of capturing oblique light rays—this leads to noticeable vignetting around the edges of the image. The effect is especially pronounced at f/2.8, but improves significantly when stopping down to around f/5.6–f/8.
這顆 Zeiss-Opton Biogon 35mm f2.8 T (Contax RF接環) 是我在二十幾年前還常在拍底片時收藏的鏡頭。它的特點就是後鏡組很突出，就快要頂到底片平面了，據悉這樣的設計是追求零畸變，成像幾乎沒有變形，且解析度極高。但這項在傳統底片時代的優勢，在數位攝影時代，因為後鏡組極度靠近感光元件，且因感光元件無法取樣斜進光線的特性，導致成像周邊有很明顯的失光現象，在光圈f2.8時非常明顯，光圈縮小至f5.6-8之後可獲得大幅度改善。
Zeiss-Opton Biogon 35mm f2.8 T (f2.8)
Zeiss-Opton Biogon 35mm f2.8 T (f5.6 or smaller)
Zeiss-Opton Biogon 35mm f2.8 T
Zeiss-Opton Biogon 35mm f2.8 T
Zeiss-Opton Biogon 35mm f2.8 T