Carl Zeiss Jena Flektogon 35mm f2.8 and Sony A7C

2026/3/22

I own three Carl Zeiss Jena lenses: the Tessar 50mm f/4, Biotar 58mm f/2, and the Flektogon 35mm f/2.8 featured in this test. The Flektogon 35mm wide-angle lens was produced in several versions. The one I have is the so-called “zebra” version, recognizable by its striped focusing ring. It has a remarkably short minimum focusing distance of 18 cm, which reportedly provides a reproduction ratio approaching 1:2. A later multi-coated (MC) version was also produced, featuring a faster f/2.4 maximum aperture and a 20 cm minimum focusing distance.

The principle behind most macro lenses is to move the optical assembly farther away from the film plane. However, this increased distance reduces the amount of light reaching the film. In other words, when shooting at a 1:2 reproduction ratio, the amount of light reaching the film is only about half of what it is when focused at infinity. Although the lens is mechanically marked as f/2.8, the effective light transmission is closer to f/4. This lens incorporates a thoughtful design feature. When shooting wide open at f/2.8, the aperture scale gradually shifts from f/2.8 toward f/4 as the focusing distance becomes shorter. In the era before TTL metering, this served as a useful reminder to photographers that they needed to compensate for the light loss by slowing the shutter speed by one stop.

Mounted on a Sony A7C and shot using Auto White Balance, the Carl Zeiss Jena Flektogon 35mm f/2.8 produces fresh, clean colors under bright morning sunlight. It faithfully renders the pale blue sky, the yellow-brown tones of bare tree branches, the vivid green grass, and the soft pink of azaleas. I suppose that is part of the enduring charm of classic lenses.


我收集的 Carl Zeiss Jena 的鏡頭有三顆，Tessar 50/4、Biotar 58/2 和這次測試的 Flektogon 35/2.8。Flektogon 35mm 廣角鏡頭有許多版本，手上這顆的外觀是俗稱的斑馬鏡，最近對焦距離是 18cm，據說是接近 1:2 的放大率，後期還有光圈 f2.4 、最近對焦距離是 20cm 的 MC 版本。大部分微距鏡的原理，就是將鏡組遠離底片平面，但較長的距離會使得到達底片光量減少，換言之，當微距攝影達 1:2 放大率時，底片的感光量只有對焦無窮遠時的一半，雖然機械光圈標示為 f2.8，但實際的感光量為 f4。這顆鏡頭在設計上有個小巧思，一開始以光圈f2.8拍攝時，隨著對焦距離越來越近，機械光圈標示會從 f2.8 移動到 f4，這在相機沒有TTL測光的年代，算是一項對攝影者的善意提醒，需要使用慢一檔快門來補償失光量。

Carl Zeiss Jena Flektogon 35/2.8 接上 Sony A7C，以自動白平衡拍攝，在上午的大太陽底下，色彩清新乾淨、忠實呈現出天空的淡藍、枯樹枝的焦黃、草地的鮮綠和杜鵑花的淡粉紅，我想這就是老鏡的特色吧。

Carl Zeiss Jena Flektogon 35mm f2.8


Carl Zeiss Jena Flektogon 35mm f2.8

Carl Zeiss Jena Flektogon 35mm f2.8

Carl Zeiss Jena Flektogon 35mm f2.8

Carl Zeiss Jena Flektogon 35mm f2.8

Carl Zeiss Jena Flektogon 35mm f2.8

Lens Comparison: Carl Zeiss Jena Sonar 85/2 T vs Jupiter-9 85/2 MC

2026/5/16

After taking the Soviet Jupiter-9 85mm f/2 MC (M42) out for a photo walk last time, I thought it would be interesting to compare it directly with the West German Zeiss-Opton Sonnar 85mm f/2 T (Contax RF), which led to this test record.　I mounted both lenses on Sony E-mount adapters for the comparison. In terms of physical size, the Jupiter-9 is about 1–2 mm taller. When stopped down to f/4, the Jupiter-9 maintains an almost perfectly circular aperture shape, while the Zeiss-Opton produces a more polygonal, star-like diaphragm opening. As for weight and handling, the two lenses feel fairly similar in hand.

上次帶著蘇聯 Jupiter-9 85/2 MC (M42) 外拍後，想到應該要與西德 Zeiss-Opton Sonnar 85/2 T (Contax RF) 比較一下，所以就做了這次的測試記錄。我將兩顆鏡頭都裝上了Sony E轉接環，就高度而言，Jupiter-9 約高了1~2mm，縮光圈至 f4 時，Jupiter-9呈現近乎圓形，Zeiss-Opton則是多角星芒狀，重量手感則是差不多。

These test shots were taken indoors under mixed lighting conditions, combining tungsten bulb lighting with daylight coming through a window. Comparing both lenses wide open at f/2, I personally find the Jupiter-9’s background rendering more pleasing, with stronger subject separation and a greater sense of three-dimensionality. The Zeiss-Opton Sonnar, on the other hand, stands out for its superior sharpness and contrast. When stopped down to f/4, it becomes even clearer that the horizontal lines behind the text are actually composed of dotted segments. I’ve also included both full-frame images and enlarged crops for reference.

All test photos below were taken with a Sony A7C with in-body image stabilization enabled (85mm setting).

這次的測試照片是在室內燈泡光源和窗戶室外光源混和的條件下拍攝的，以光圈f2來比較，我覺得 Jupiter-9 對背景虛化的處理比較令人討喜，也較有立體感，而Zeiss-Opton Sonnar 則是勝在銳利度和反差，縮光圈到 f4 時更可以清晰地看到文字後的橫線是點狀虛線所組成。同時附上全幅和放大裁切後的相片給大家參考。

以下測試照片均以 Sony A7C + 防手震啟動(85mm) 拍攝


Jupiter-9 85/2 MC at f2, 1/250, ISO400


Jupiter-9 85/2 MC at f4, 1/60, ISO400


Zeiss-Opton Sonnar 85/2 T at f2, 1/250, ISO400


Zeiss-Opton Sonnar 85/2 T at f4, 1/60, ISO400

Center crop at 100% magnification:

擷取影像中間，100%放大後：


Jupiter-9 85/2 MC at f2, 1/250, ISO400


Jupiter-9 85/2 MC at f4, 1/60, ISO400


Zeiss-Opton Sonnar 85/2 T at f2, 1/250, ISO400


Zeiss-Opton Sonnar 85/2 T at f4, 1/60, ISO400

MC Jupiter-9 85mm f2 and Sony A7C

2026/3/22






My third collectible Soviet lens is the Jupiter-9 85mm f/2 MC, a lens with a strong lineage tracing back to the pre-war Carl Zeiss Jena Sonnar 85mm f/2 made for Contax RF cameras. This particular copy was manufactured in the late 1980s and features MC multi-coating. Although the exterior shows heavy signs of wear, the optics themselves are actually quite clean. When I first received the lens, the aperture scale and index mark did not line up correctly. I spent quite a bit of time disassembling the entire optical block and aperture ring, then recalibrated and reassembled it so that each aperture marking now aligns perfectly with the indicator.

The most distinctive characteristic of this lens is its rendering wide open: contrast is very low and the image appears soft and dreamy, but once stopped down, the contrast improves significantly. In the first photo, the background blur behind the uBike bicycle seems to “melt away” into the distance, while the highlights carry a slightly creamy texture with a hint of swirl, producing an exceptionally smooth bokeh.

我收藏的第三顆蘇聯鏡頭是Jupiter-9 85mm f2 MC，與戰前的CONTAC RF相機接環的Carl Zeiss Jena Sonnar 85mm f2有著濃濃的血緣關係。這顆鏡頭是上個世紀80年代後期製造的，有冠上MC鍍膜，雖然外觀磨損的很厲害，鏡片倒是蠻乾淨的。這顆鏡頭剛到手時，光圈環的數字和指標位置有些差異，我費了一些功夫拆下整個鏡組和光圈環，將光圈環重新鎖定在正確的位置，讓每個光圈環的數字和指標都能對得上。

這鏡頭最大的特色是在光圈全開時，反差很低、很柔和，但縮光圈後反差也就好很多。第一張照片uBike腳踏車背後，散景一路往後「化開」，高光邊緣帶一點奶油感與旋轉感，非常滑順。

Industar-61-L/Z MC 50mm f2.8 and Sony A7C

2026/3/22





My very first Soviet lens collection piece, the Industar-61 L/Z MC 50mm f/2.8, is back in action. I took it for a walk around the National Taiwan University campus to soak up some sunshine. Under bright sunlight, using the sparkling highlights filtering through the leaves as the background, this lens can produce its signature “star-shaped bokeh” effect.

Over the past few years, NTU has been undergoing constant redevelopment. Old buildings have been demolished one after another, while new buildings funded by alumni donations continue to rise. Even NTU Xiao-Fu, where I used to bring my kids on weekends, has been torn down. Over these past two decades, my photos of the NTU campus have gradually evolved from Fujifilm slide film and peel-apart film to digital photography and Instax film.

我收藏的第一顆蘇聯鏡頭 Industar-61-L/Z MC 50mm f2.8 又出動了，帶它來台灣大學校園走走，曬曬太陽。在大太陽下，以樹葉的點狀反光作為背景，就可拍出這顆鏡頭特有的「星狀散景」效果。

這幾年台大持續大興土木，老舊建築一棟一棟的拆，校友捐贈的新大樓一棟一棟的蓋，以前週末溜小孩的台大小福也拆掉了。這二十幾年來，我拍台大校景的照片也從富士正片、撕拉片，漸漸得變成數位相片、Instax底片。不變的就是手上的四十幾棵手動對焦老鏡頭，拜各種轉接環之賜，得以在數位相機和拍立得相機上復活，使得一些傳統優質老鏡的價格也水漲船高。


Industar-61-L/Z MC 50mm f2.8


Industar-61-L/Z MC 50mm f2.8


Star-shaped bokeh, Industar-61-L/Z MC 50mm f2.8


Industar-61-L/Z MC 50mm f2.8

Zeiss-Opton Biogon 35mm f2.8 T and Sony A7C

2026/3/22

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


Zeiss-Opton Biogon 35mm f2.8 T on Sony A7C

Sony A7C, Konica Hexanon 35/2, Voigtlander Color-Heliar 75/2.5 Combination 外拍組合

2025.7.27

The Sony A7C is my second Sony full-frame digital camera. I bought it because its lightweight body (compared to the Sony A7III) is perfect for adapting classic RF film camera lenses, such as Leica M39 lenses or Contax/Nikon RF lenses. Pairing the silver-and-black camera with two silver lenses for outdoor shooting feels like stepping back into the 1950s — a perfect match.

Traditional RF film cameras have a physical limitation in close-up photography because the optical axis of the lens and that of the rangefinder window are not the same. As a result, most lenses are designed to focus only down to about 0.9–1 meter. Nowadays, many lens adapters are designed with a focusing helicoid, which allows the focusing range to extend by about 5 millimeters when the lens is mounted on a digital mirrorless camera, shortening the minimum focusing distance by several tens of centimeters and adding even more enjoyment to shooting.

Sony A7C 是我的第二台 Sony 全幅數位相機，購入的原因是她輕便的機身(相較於Sony A7III)非常適合轉接傳統RF底片相機的鏡頭，例如Leica M39鏡頭或Contax/Nikon RF鏡頭。銀黑色的相機搭配兩顆銀色鏡頭外拍，彷彿回到了1950年代，真是絕配啊。傳統RF底片相機由於鏡頭的光軸和測距窗的光軸並不一樣，在近距離拍攝上有物理限制，因此大部分的鏡頭在設計上僅能對焦到0.9~1米。現在很多轉接環在設計上都加入的調焦功能，當鏡頭裝在數位相機上時對焦可以再延伸約5毫米，讓最近對焦距離可以縮短數十公分，在拍攝上的樂趣就更大了。

Sony A7C and Lens Combo

Sony A7C, Konica Hexanon 35/2

Sony A7C, Konica Hexanon 35/2

Voigtlander Color-Heliar 75/2.5

Voigtlander Color-Heliar 75/2.5

Canon PowerShot G16 + TC-DC58E @ Badaozi Fishing Port 八斗子漁港

20250501

This Canon PowerShot G16 digital camera, launched in 2013, has been with me for over a decade. I've changed its lithium battery three times, and currently, all functions are still working well. Despite the convenience of immediate editing and uploading with an Apple iPhone for everyday photography, which has become a handy tool, I still often take this digital camera out to experience the feeling of operating a camera. The Canon PowerShot G16 features a 5x zoom lens with a 135 equivalent focal length of 28mm-140mm. To maintain image quality without using digital zoom, I can attach the original 1.4x teleconverter lens (TC-DC58E) from Canon, extending the telephoto focal length to 196mm.

這台2013年上市的Canon PowerShot G16隨身數位相機，我已經使用了十幾年了，鋰電池也換過三輪，目前各項功能都還很正常，雖然Apple iPhone手機拍的照片具立即編輯和上傳的便利性，已經成為日常生活照的攝影利器，有時候我還是常常帶這台數位相機出門，回味一下操作相機的感覺。Canon PowerShot G16的鏡頭具備五倍變焦，135等效焦距是28mm-140mm，為了能夠在不使用數位變焦，維持原解析度的影像品質下，可外掛原廠1.4倍望遠鏡頭(TC-DC58E )，讓望遠的焦距達到196mm。

Canon PowerShot G16

Canon PowerShot G16 + TC-DC58E (1.4x Tele-converter)

During a recent visit to Keelung's Badaozi Fishing Port, I exclusively used the Canon PowerShot G16 + TC-DC58E for photography. The weather that day was overcast, and the camera's white balance faithfully portrayed the simple fishing port, lacking the vibrant tones of smartphone photos, which made it feel like a true representation of what was seen. Several small fishing boats equipped with high-wattage lights were moored in the port, used for attracting light-sensitive fish or squid during nighttime fishing, also known as 'lantern fishing'.

這次到基隆八斗子漁港一遊，就完全使用Canon PowerShot G16 + TC-DC58E來拍攝。當天天氣是陰天，相機本身的白平衡忠實的呈現樸實的漁港，少了智慧手機照片的鮮豔色調，讓人感覺到這才是真正的所見及所得。漁港內停了數艘釣小管的漁船，船上裝載有高瓦數的電燈，夜間可吸引趨光性的魚群或小管靠近捕撈，也稱作燈火漁業。

Auto CHINON MC 55mm f1.7 M42 on Sony A7III

2024/6/9

Today, I took my CHINON 55mm f1.7 lens, which I've been collecting for years, out for the first time to shoot some flowers and plants. After attaching a 12mm extension tube and an adapter, I mounted it directly onto my Sony A7III digital camera. This setup basically turns it into a macro lens with a magnification of around 1:4 to 1:2.5. If I switch to APS-C mode, the magnification goes up to about 1:1.5, making it easy to capture close-up shots of the little yellow daisies (Wedelia) like the one shown here.

今天第一次帶著收藏多年的CHINON 55mm f1.7出門拍些花花草草，裝上12mm的延伸環和轉接環後直上Sony A7III數位相機，基本上就是約1:4~1:2.5的微距鏡頭了，如果再切換到APS-C模式，就是1:1.5左右的倍率，很容易就可以拍出以下小黃菊(蟛蜞菊, Wedelia)的近拍照。


Auto CHINON MC 55mm f1.7 + 12mm extension tube

I hadn't paid much attention to this lens before, mainly because I bought it along with the CHINON CM-3, an M42 film camera. Since CHINON was primarily an OEM for cameras and lenses, and its own brand was often associated with budget cameras and lenses, I didn’t particularly care about the optical quality of this lens. However, after recently researching this 55mm f1.7 lens online, I came across a claim that it was manufactured by the renowned Tomioka Optical. This piqued my interest, and I decided to give it a try.

以前沒有特別注意這顆鏡頭，主要是因為它是跟CHINON CM-3這台M42底片相機一起購入，由於CHINON本身是相機和鏡頭代工廠，自主品牌則常是廉價相機鏡頭的代表，我對這棵鏡頭的光學品質並未特別在意。前這子網路上查詢這顆鏡頭的資訊時，看到一種說法，即這顆55mm f1.7的鏡頭是有名的富岡光學代工，也就興起了試拍的念頭。


Auto CHINON MC 55mm f1.7 M42

In June, before the peak of the hot summer, the pathway along the Sunshine Bridge in Xindian is lined with blooming little yellow daisies. The insects are also drawn to the flowers, lingering and flitting back and forth.

六月天，在進入炎熱的夏季前，新店陽光橋下的步道沿線都是盛開的小黃菊，蟲兒也受到了吸引，流連往返。

Auto CHINON MC 55mm f1.7 + 12mm extension tube


Auto CHINON MC 55mm f1.7 + 12mm extension tube


Auto CHINON MC 55mm f1.7


Auto CHINON MC 55mm f1.7