Now this is a puzzling lens - put on a Fujifilm GFX 100 camera, by Thomas Lövgren at Cyberphoto he took in Umeå. This lens is a Contax/Yashica lens for 35mm cameras, but he tested it on a Fujifilm GFX 100 (102 MP) camera. Used at wide open aperture; it appears to cover almost the entire sensor. Only in the extreme borders you can see a very, very slight touch of blur.
Once stopped down, it gets sharp-sharp. Everywhere !
I've rarely seen a 35mm type of lens that does such good work on a mediumformat sensor. I was truly intrigued. I simply didn't expect that from a 35mm type of lens.
You can see examples yourself at his blog about this lens, at Cyberphoto.
Carl Zeiss Sonnar T* 100/3.5 mounted on a Fujifilm GFX 100 camera
I mean, the results are astonishing
The lens itself is highly compact, has a 55mm filter, and a close up distance down to 1 meter. On top of that, I like the second hand prices ($ 230 before tax) seen from a perspective of a mediumformat capable lens. (On the GFX the focal length turns into a 80 mm lens, e.g. gets a bit wider) The background blur behaves like that of a 80mm ƒ 2.8 lens.
Aperture blades, AEJ vs MMJ versions
The only relative "drawback" are the 6 aperture blades. As you stop down, any highlights among the background blur looks a bit funky. The AEJ version of this lens (made in Germany, for Contax cameras), will have so called "Ninja" look; a strangely looking jagged form in highlights. The latter MMJ version (made in Japan), does not have that. Here the aperture f22 on the lens is painted in green color. That's a way to distinguish the different versions.
Usually 35mm vintage lenses from other brands, are much, much cheaper today; often below $90 and less. (But most of the time they don't perform very well on a GFX camera ! With a few exceptions)
In the image example above
which by the way is made in higher resolution than i normally use in my Diary - just in order to show you the finer details - showing you the finer details and good sharpness. Plus i used the 6x6 form factor - but the left border is the real border from the GFX 100 image. (So you would see the lens performance at the border better)
Best would be, if you checked the original images (ƒ3.5, ƒ5.6, ƒ8 and ƒ11) that Thomas Lövgren published on his blog at Cyberphoto. They are all in native 100 MP resolution.
In fact; The tested TONS of other vintage glass with the GFX 100 - published with many image examples on his blog.
It is a very long list - including some really scurrilous lenses !!
Additionally; the shows high-res images of objects that are approx. 1 meter away, in order to show the performance at closer range. (Vintage lenses often perform less good when focusing close) Albeit in the case of the Carl Zeiss Sonnar 100/3.5 lens - it performs very well already at wide open aperture ƒ3.5
Then, it only gets better when stopping down the aperture.
Specifications
- Diameter: 62.5 mm
- Length: 61 mm
- Weight: 285 g
- Filter Diameter: 55 mm
- Number of Aperture Blades: 6
- Elements/Groups: 5/4
- Close Focusing Distance: 100 cm
- Mount: Zeiss C/Y
Were only made in 7070 examples
Oh, another detail i remember from searching countless sites on the internet lately is, that the C/Y Carl Zeiss Sonnar T* 100/3.5 was only made in 7070 examples. Apparently it was a relatively unknown lens with low demand. Most people were staring at the much brighter ƒ2.0 version of this lens back in the 70s and 80s.
C/Y stands for the camera mount; in this case C/Y lenses work on both Contax and Yashica (film) cameras.
No info on this combo elsewhere
The lens performs stunning already at wide open aperture ƒ3.5 - given it is a 40 year old lens made for a 35mm film cameras. Notice that the only correction Thomas Lövgren has done to his published images is vignetting correction.
So, I have no clue of how the image looks like with its native vignetting (darker corners) left untouched. There is basically no information or image examples available on the internet, using the particular C/Y Carl Zeiss Sonnar T* 100/3.5 lens on Fujifilm GFX cameras.
Tested on fullframe (sensor)
One test i found - but only on fullframe: Famous phillipreeve.net who tested the Carl Zeiss Sonnar 100/3.5 with a Sony fullframe camera. (And he makes often stunning images - talk about a photographer who often is out and about. I admire that). One of the hallmarks of this lens according him was the very evenly distributed sharpness across the frame, and lovely even bokeh, low flare behavior and very flat field sharpness.
I can think of this
as a summer time lens for my Fujifilm GFX 50s II camera, due to the compactness, and its stunning optical performance. An easy to grab lens when going out / or using it after my night-shift work, during early summer mornings.
| 
