Photo Cinema reproduct lens [Mu-Yichi-Kyo]
Founded in January 2012
Photo Cinema reproduct lens [Mu-Yichi-Kyo]
Founded in January 2012
The Fourth Kino **DE401630**
Since we cannot use names that are subject to trademark rights, we have decided to use a format such as "**DE401630**" that clearly indicates the source of the data. We apologize for any inconvenience this may cause. - 2025.3.17
This is the posthumous work of Paul Rudolph, It is the last Kino **DE401630**. The calculated aperture in the patent is f1.0, but it is impossible to produce, and the aperture is unique at f1.2-2.8, and it is quite a large cannon (it is about 6.5cm from the flange to the front lens, so it is a cylindrical cannon). The depiction shows the tranquil appearance of the Kino **DE401630**.
In the obituary of Paul Rudolph in the spring of 1935, it was mentioned that the last lens he worked on was the "Rapid **US1833593**" (US Patent US1833593). This design was rejected by the German Patent Office. It was described in data sheet 858, which Merté had personally produced and is kept at Zeiss, and had a field angle of about 30 degrees. It was designed while he was still employed by Mayer, and it is known that Mayer sold a 12mm f1.1 for 8mm film. This is equivalent to 70mm. The patent application was approved in the United States. The aperture is described as f1, but Merté points out in the table of contents of the data sheet collection that it is actually about f1.2.
Dr. Rudolph when he was about 40 years old. The Rapid was made in his later years and was not taken with a Rapid.
This is Kino **DE401630** for small film sizes. Kino **DE401630** also comes in 12.5mm for 8mm movies, but as the lens gets smaller, it loses its appeal and the film becomes smaller, resulting in poorer images, so I think they thought they had to make something specialized to make up for that. They tried to develop the best lens for commercial reasons, expecting that 8mm cameras would become more popular in the future. In that sense, it can be said to be an enhanced Kino **DE401630**. The lens is small for small films, but it is well-designed, so when it is scaled up to 35mm, it becomes huge, and it becomes irrational to use a lot of heavy and expensive glass. In that sense, it is for small films. However, I experienced the greatness of Kino **DE401630**, and being able to see in a larger size what I created to capture the rich, solid images in 8mm makes me want to reprint this as well.
The drawing is of the size that will actually be manufactured. You can see that the aperture does not fit all the way in. The lenses are touching (they are not touching during manufacturing). The patent description states that the aperture can only fit partway in, so it is necessary to use a modern type of rotating aperture. It also warns that the glass must not be pressed together (it will expand and crack when it gets hot). It can go up to f2.8. It is an incredible lens with f1.2 to f2.8. If you use this in broad daylight on a sunny day, you will need a very fast shutter speed, which is possible today but would have been impossible in the past. Therefore, you can see that it was not designed for use with stills. However, for movies such as 8mm, it is difficult to focus the light because of its small size, and it becomes dark. It means that it cannot be used unless it is this bright.
院落 Yinraku P3 60mm f1.2 356,000円
Dedicated hood included. Filter diameter 62mm. Minimum shooting distance 0.5m. Straight helicoid. Aperture blades 12. Actual weight 567g.
Although the thickness, spacing, and lamination position of the glass are different, you can see that the lens structure is the same. The lamination is done to adjust for chromatic aberration, so its presence on other aberrations is quite limited and generally unrelated. The scale is the same, so you can see how huge and thick the Rapid glass is. It looks like it will produce a rich and dense image. Both are set to a focal length of 50mm.
The actual product is 57mm (marked as 60mm), so the glass is a little larger. The recommended length is 70mm (about 32.5 degrees angle of view) (Kino **DE401630** seems narrower), but I thought that this might be too long, so I decided to go with a 39 degree angle of view, which is about 3 degrees wider at half the angle of view.
There are two other types of Kino **DE401630**, but they also have the same basic structure. According to the patent data, Kino **DE401630** was the third Kino **DE401630**. Rapid **US1833593** was the fourth, and Dr. Rudolph's last Kino. Looking at the beauty of Kino **DE401630**, it is a tragedy that the last Kino has not appeared in the world. It makes me have high expectations for how beautiful it will be.
Kino **DE401630** was sharp in terms of focus. In contrast, Rapid **US1833593** has a spherical aberration (left) of about -1mm, which can be considered to be in the category of soft focus (modern soft focus lenses have a more serious bokeh effect, so from that perspective it is not soft focus at all. The image is similar to Leica Summarit, which is designed to have a large aperture, and the residual aberration makes it slightly soft. It seems close if you think of it as a lens that has organized the design and made good use of that). At f1.7, the chromatic aberration disappears almost completely, but the spherical aberration is maintained up to that point, and from there the spherical aberration decreases up to f2.8, and when stopped down it becomes closer to Super Six. The refractive index of the glasses used in Super Six is not very different, but the refractive index of the glasses used in Rapid **US1833593** is the same. Both designs use only two types of glass with different dispersions. The tangential line (dotted line) in the astigmatism diagram (center) is the same as the sagittal line of Kino **DE401630**, and the other line is inverted. It is aligned in the same direction as the spherical aberration. This is how we get a flat surface, but there is too much aberration, so it is not flat.
The focal width of the Kino **DE401630** is narrow, but the Rapid **US1833593** has a wider focal width because the glass spacing is narrowed so that the aperture does not reach the back. The glass spacing of the Kino **DE401630** is wider at f1.5, so the impression is likely to change.
The aperture is specified as f1, but as Merte pointed out, f1.2 was the limit. It does not cover 44x33. It is a cylindrical giant gun with the rear lens sticking out more than 6cm near the flange. The filter diameter is 62mm (even the Summarex is 58mm), so Leica rangefinders can be used, but there is a lot of vignetting in the bottom right of the viewfinder.
The design value for the glass transmittance is 100%. Even with coating, there is a small loss, but without coating, f1.2 becomes f1.5 (labeled T1.5) with a transmittance of 72%. However, the label is left as f1.2. This is because in aperture-priority AF, the shutter speed is automatically adjusted, so there is no need to consider it, and transmittance and depth of field are unrelated, so the thinness of the focus remains f1.2. In any case, f1.2 is too bright, and even if you narrow it down, it only goes up to f2.8. Without coating, it becomes about T1.5 to 3.5, which should be easier to use. T1.5 is quite bright even at night.
Kino **DE401630** has five types: f2, f1.5, Rapid f1.2, and the f2.5 described in the f2 patent is probably soft like an old Leica, and the other f1.7 is over the Rapid's under, so it would have been highly rated if it had been preserved in modern times. The aberrations of the Rapid **US1833593** also start at f1.7, so f1.7 may have been an important point in terms of soft focus, which makes use of spherical aberration.
