Melvin Jones

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August 31st 2020

At the time when the autofocus technology is so mature, there must be some special reasons to choose a manual focus lens. For Voigtlander APO-LANTHAR 50mm F2, this reason is written in the lens name.

APO is the abbreviation of Apochromatic, which means "apochromatic". The function of APO lenses is to correct the frequencies of the three primary colors of red, green and blue at the same point to reduce chromatic dispersion. Therefore, in the shots of Voigtlander series, three slashes of red, green and blue can be seen.

This 50mm F2 is Voigtlander’s third APO lens. The first two 110mm APO and 65mm APO are both macro lenses. Because they are not commonly used focal lengths and longer focus strokes, they are relatively niche.

And this lens uses a standard focal length, the focus stroke of about 140 ° is easier to operate, and the weight of 364g is also very advantageous in terms of portability. Although they are all manual lenses, they obviously make you want to shoot.

As a purely manual lens, there are not many details to introduce in terms of appearance. The focus ring adopts an etching process, which is a very retro design, popular in the 1930s, and it can be regarded as an old tree budding when used on this lens. The focusing feel is very smooth, the closest focusing distance is 45cm, which is not too close, but it is good enough.

The iris ring adopts a completely manual adjustment method, 1/3 step. This lens has a more interesting design. The 12 aperture blades are specially designed. In addition to the maximum aperture, it can form a complete circle when it shrinks to F2.8, but it will not be large or small.

Although it is a manual lens, because it is a native E-mount, it also has electronic contacts, which can transmit some EXIF ​​information with the body. On the mount, we can see the logo of "True Master" COSINA.

The lens structure should be the biggest highlight of the 50mm APO. There are 2 aspherics and 5 ultra-low dispersion lenses in 8 groups of 10 lenses.

From the lens structure, we can see the shadow of the double Gaussian. Special lenses are used for correction at the front and the end. This is a very pile-up design. Of course, when it comes to APO, we have to mention Leica. Leica's 50 double A uses an optical design of 8 elements in 5 groups.

Compared with the two lenses, although both are based on double Gauss, Leica uses less materials and uses more gluing processes. Voigtlander uses stronger materials. For APO lenses, the more materials used, the higher the assembly accuracy is required. At the same time, there is no problem of the paraxial focus baseline. The close-up distance can be made closer, and the closer focus is also required. Make certain optimizations.

Resolution test

Test instruction:

The previous traditional lens tests were done by turning off the body correction as much as possible, or even detaching it from the body more extreme (such as Lensrentals' MTF scanner, the first unified adapter we used) to obtain "the image quality performance of the lens itself."

However, with the continuous electronicization of camera systems, the combination of fuselage lenses and methods to improve image quality has become more and more mainstream, and then entangled in the "native image quality" of the lens, many times I have to say that it is a bit out of date.

So from this time, we use the following test method:

1. All adopt native bayonet body to shoot RAW files

2. In the resolution test, turn on the configuration file of the ACR or the built-in correction of the RAW file (for distortion), and turn on the dispersion correction (for the chromatic aberration of magnification). If the two configuration files do not exist, manually correct the distortion according to the reference line on the target plate, and manually correct the chromatic aberration of magnification according to the visual result .

3. After considering the influence of distortion correction and chromatic aberration correction on resolution, the final resolution test result is output. The original magnification dispersion (after turning off the correction that can be turned off) and the distortion value are given together, for reference only (to prevent the dispersion from being too large to roll over in a large light ratio environment).

4. The axial (out-of-focus) dispersion test is reserved.

 The data review part highlights the characteristics of our semi-quantitative test for use (quantitative data is the means, qualitative review is the purpose), divided into "overall quality" according to the related use of the lens (see the overall resolution level of this lens in the same specification or Where is the column of similar specifications lens), "resolution-focal length distribution fit" (whether the high-resolution focal length of this lens is suitable for its main shooting subject), "resolution-aperture distribution fit" (this lens Is the best aperture suitable for its main subject? Three-part comment. Each review will be given a qualitative rank (from low to high, five levels are "bad", "low", "medium", "high", and "extreme") for people who don’t know the data very well. The necessary information.

Resolution data information comments:

For lens purposes: standard large aperture, street sweeping, portrait, on-hook lens

Overall quality: high, because it is a manual focus lens, it is unfair compared to products of the same specification, but from the perspective of resolution performance, whether it is the maximum aperture or the best aperture, it is indeed very good.

Resolution-focal length distribution fit: high, the center and 35% of the area have a very high resolution level. If you are picky, it is more serious than the 95% edge area of ​​the center image field.

Resolution-aperture distribution fit: high, there is already a resolution level of 3000LW/PH under the maximum aperture, and the resolution is basically the same under the first three apertures, which is a relatively rare result. However, with a high-pixel camera, when the aperture is reduced to f/8, there will be a significant attenuation.

Other project testing

Dispersion

The magnification chromatic aberration of Voigtlander 50APO is: 4.62μm

The axial chromatic aberration of Voigtlander 50APO is: 7.73μm

Vignetting

The full aperture vignetting angle of Voigtlander 50APO is: 1.96EV

distortion

The double distortion of Voigtlander 50APO: -0.62%, slight pincushion distortion

Out of focus

The out-of-focus performance has a certain caliber erosion and field curvature. If you zoom in, the grinding accuracy of this lens lens is still relatively high.

Real shooting experience

From the measured data, although the running score of 50APO is very high, the data is cold after all. If you want to experience the charm of this lens, you must look at its real shooting effect. Different from the working distance in the laboratory, I mainly want to see the performance of this lens at long-range focusing and close-up shots during real shooting.

1/8000s; F2; ISO100

Different from the usual shooting habits, I basically used this lens to shoot at full aperture when I tried it, and the body used was α7R III. Let's take a look at the remote scene first, the focus position is shifted to the bottom 1/3 of the screen. The above picture shows that the vignetting of this lens is still relatively heavy when the aperture is fully opened.

Partially enlarged screenshot

It can be seen that in this usage mode, this lens also has a very good resolution performance. Of course, this performance does not give people a shocking feeling. Let's take a look at the imaging effect when shooting at close range.

1/1600s; F2; ISO100

The same aperture is fully opened, and the focusing distance is about 50cm, because the blur effect is more obvious because of the close-up. But the image at the focal point is still sharp. The sharpness of APO gives people a feeling that is beyond the perception of the human eye. Only when you zoom in to view the details can you really experience this impact.

Partially enlarged screenshot

In addition to the excellent resolution performance, the imaging transition of this lens from in-focus to out-of-focus is also relatively natural, without a feeling of rigidity. This is the second thing I like about APO. In addition to "silly and sharp", I can feel some sense of atmosphere.

1/500s; F2; ISO100

In terms of imaging style, this is a relatively high-contrast lens. Although it is a Japanese-owned Nissan, it retains the high contrast of the German brand. A little adjustment in the later period is a relatively heavy tone style.

1/3200s; F2; ISO100

1/3200s; F2; ISO100

In terms of dispersion control, although this lens is made of tough materials, some slight magnification dispersion can still be seen when the aperture is fully opened. Axial dispersion can refer to our laboratory data.

The starburst performance of this lens surprised me a bit. Although it has 12 aperture blades, the starburst is the feeling of an old lens, and it is really obvious.

1/50s; F11; ISO100

To Sum Up

Voigtlander APO-LANTHAR 50mm F2 is a product that combines classical appearance and modern optical design.

With multiple lenses available in the same focal range, this APO can bring you a completely different picture quality experience. It is not an all-rounder, but it gives a visual explosion impact in terms of resolution. As long as the focus is accurate, the world will be sharpened. This is the charm of the so-called apochromatic lens.

There is a saying in the wizard circle, "Take a picture, don't we just take a sharp picture". If you like this imaging style, 50mm APO has every reason to let you abandon the autofocus function. However, for the mirrorless body, it is still difficult to take portraits, and it depends on the individual's level to control it.

Therefore, this lens is destined to be a niche toy. If you are also holding a ticket mentality, relative to its price of about $1049, you might as well rent it for one experience. You will definitely have a different feeling.

If you like this article, please check our review of Sony a7S III

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