Re-issuing the classic wide-angle lens
「花影」Hanakage S2 28mm f5.6
2025.03.15
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
It is difficult to find an ideal wide-angle lens among classic lenses. Looking at various wide-angle lenses from the past, we found that the ideal ones are as shown in the following Characteristics of Classic Wide-Angle Design. As a result, we found that the two old Leica 28mm lenses are particularly excellent. However, we would like to manufacture something that goes even further than that. There are several options for the characteristics of classic wide-angle lenses, but there are two areas to consider in the design.
One is the aperture; is f4 possible? If you want to maintain high performance with this brightness at 28mm, you need a very thorough design, and even if you use a Biogon or Eetrofocus type, you will need a lot of glass. Angénieux has achieved f3.5 with just six pieces of glass, but since there is no glass bonding, coating is required. At 28mm f4 is basically a blur in a negative sense. The optimal solution based on the laws of nature for 28mm seems to be f5.6.
Another issue is the choice of whether to make the curvature positive or negative. In designs for medium format and smaller cameras, the curvature is negative, but I think this is a factor that reduces the appeal of the neat images produced in this way. Leica made the curvature positive, which has left a deep impression to this day.
Doing so will satisfy the conditions. The result is shown in the figure below. This is the image at 28mm. There is a fair amount of aberration, but they are offset in a complex manner, resulting in almost no aberration on the sensor surface. Unless the lighting environment is extremely poor, vignetting is unlikely to occur. The aperture is positioned inside the flange. It goes in about 1cm. The length that protrudes from the surface is less than 7.5mm. Therefore, the hood is integrated with the lens barrel.
Filter diameter ?mm. Minimum shooting distance ?m. Aperture blades ?. No glass coating. Actual weight ?g.
For macro, if you are 150mm from the tip of the lens, it will be about f6.8 at full aperture, and if you get closer to 100mm, it will be about f7.8, but I think it is usable because the aberration will only increase slightly. I don't think there will be any use for this, so I think it will be enough to get closer to 500mm (same f6.0). If you use the
Rayqual close-up ring +3mm, it will be 280-235mm (this design has a lot of aberration, so there is a significant discrepancy with the description on the Rayqual site).
Even at full aperture, if you set it to about 5m, the depth of field will range from infinity to around 2.5m. That's just a little beyond the height of a human being. For most things, there's no need to adjust the distance. If you set it to 3m, it's 2-8m. At 2m, it's 1.4-3.5m. These are calculated values, and since this work has a lot of aberration, the depth of field is actually a little longer. For this reason, rangefinder coupling is not supported. This is probably why wide-angle photography is easy.
UV transmittance：380nm 50.04% 370nm 37.31% 360nm 14.93%。Chromatic aberration is minimal.
We have selected glass that is extremely weather-resistant. The lens barrel design has been relatively simple and cylindrical with few bumps, but since this is a design that people don't get tired of, we intend to continue this design for this model as well. In other words, the part that corresponds to the hood will not open like a trumpet, which is common with wide-angle lenses. A trumpet shape may be noticeable from the surroundings when shooting. We will discuss the details with the factory, but we are thinking of making it like the unbroken Colosseum in Rome. In short, it is just standing upright. If this is not possible, it may open a little. In any case, I think it is best to have only the bare minimum you need.
Characteristics of Classic Wide-Angle Design
In the past, due to restrictions such as the large size of the camera and the slow shutter speed, the use of photography was roughly limited to portraits and landscapes. Therefore, Petzval designed and specified these two types. The reason why these designs are hardly considered in modern times is because they were designed specifically to limit the subjects of photography. The portrait lenses remained after the war for use in movies. The landscape lenses also remained mainly as wide-angle lenses. The more time went by, the better Petzval's theory became. In the early days, wide-angle lenses were thought to be used to take landscapes and architecture, and it was unclear what else they could be used for. However, when bright wide-angle lenses could be made, they began to be used for portraits, and the way they were viewed changed. They became versatile enough to take anything regardless of the angle of view, and this tendency became even more pronounced with the support of AF. In exchange for this, the beauty that was once unique to large wide-angle lenses disappeared.
According to the laws of nature, it has been clear for over 100 years that
f2 is the limit for a focal length of 50mm, and that this is where it naturally falls. There are beautiful f1.5 lenses for medium telephoto lenses. Does this mean that brighter telephoto lenses are more attractive? I don't know, but I think that would make it an astronomical telescope, but a large aperture telephoto lens has a narrow depth of field, making it difficult to use for general purposes. On the other hand, what about wide-angle lenses?
For 28mm, the limit is probably f5.6, and I get the impression that f4.5 is equivalent to f1.9 for 50mm. If you want to get a so-called "proper" wide-angle lens, f5.6 seems to be the "common sense" spec. There are many wide-angle lenses available today that are brighter and have clearer images all the way to the corners, but if you want a lens that you won't get bored of, you can't help but be aware of the limit of nature.
From the perspective of prioritizing naturalness, if you are looking for a straightforward depiction without the use of coatings,
a lens configuration of around four groups is the limit. Increasing the number of elements too much will increase attenuation, which will also move away from naturalness. I also feel that it is easier to avoid an arbitrary feel if you limit the glass used to
classic glass made by Abbe and others around the end of the 19th century.
If you want the ideal lens configuration, you should make
the front and back exactly the same, sandwiching the aperture that Hoof continued to apply to
Dagor. This is an old model, so it was made in large quantities with errors and matched individually, but by making it the same type, the depiction is neater. It will no longer be forced. However, if you make Dagor wide-angle, the mass of the glass will be too small and it will lose its flavor, so Orthometar type is a good choice for Dagor derivatives. It can make a very excellent wide-angle lens, so this configuration has been used for aerial photography for a long time. It is also widely used in large format lenses, and
Fujifilm says in its patent description that
Orthometar is almost the same as Dagor. In fact, the only difference is that there is one air gap.
When it comes to choosing glass,
a glass with a gradual change in refractive index like Dagor will produce a more beautiful depiction. One reason why classic glass is natural is that the difference in refractive index is kept within a certain range. The uninterrupted flow of rising and falling light produces a straightforward depiction.
The aberration arrangement of classic wide-angle lenses tends to be almost the same. It is enough to compare them. From there, factors such as lens construction have biased. Since such lenses are no longer made, people have reaffirmed the merits of the Leica Summaron 28mm, and Leica has officially reissued it despite its f5.6 specs. And it has been on sale for quite a long time. Below, we will standardize the focal length to 50mm.
Petzval's design is described in No. 77 of Turriere's book. Even though it is called a wide-angle lens with f8.1, the focal length is 50mm in Leica format. There seems to be a lot of aberration, but it is offset to obtain a flat image. However, it is not perfect.
This is
Perigraphie by SOM Berthiot. It's f14.
Leica
Hector includes a wide-angle design, 40mm f8. It was released at 40mm. Mey be it was improved from there to 28mm f6.3.
The design that seems to be
Globe **DE456912** has an angle of view of 90 degrees at f6. The curvature is on the negative side. In the large format era, it was positive, but for medium format and smaller, negative is better, and that is how it has changed. Although it is slight, it seems that the negative angle makes the image closer to flat. Since large format is large, it is not as severe against flat surfaces, so a slightly more aggressive arrangement is more attractive, and for medium format and smaller, a more subdued arrangement is easier to get a sense of performance. However, it is very slight. When it comes to choosing which to go for, I think that is why other
**DE456912** and older Leicas have a curvature that is on the positive side.
This is the
Ektar 55mm f6.3 designed for Hasselbrad.
Makro **DE456912** has small aberration for landscape photography. The longitudinal aberration diagram is for macro photography.
Paul Rudolph designed the Planar while working at Zeiss, but unlike later
Planar, it was for close-up photography. At best it was good for group photos, and could be used for close-up copying. It was thought that it was not suitable for distant scenes, but this aberration arrangement was for landscapes. It is thought that it took advantage of the aberration of landscapes to make precise copies, but it seems that he thought it could also be used for portraits, and sold it. It seems that this is where he ended up with
Kino **DE401630**.
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