MINOLTA SONY

The Ultimate Guide to the SONY Distagon T* FE 35mm F1.4 ZA vs SONY FE 35mm F1.4 GM - Optical Design Value Analysis No.061

This is a performance analysis and review article of the SONY Distagon T* FE 35mm F1.4 ZA vs SONY FE 35mm F1.4 GM.

You hardly understand the specific differences in how the lenses work and how their performance differs from each other, do you?

Even if you look it up in magazines or on the Internet, all you will find are similar "word-of-mouth recommendations" and articles like that.

In this blog, while researching the history of lenses and their historical background, we estimate lens design performance based on patent information and actual shooting examples, and analyze lens performance in detail from a technical viewpoint through simulations.

Professional lens designer Jin Takayama will carefully unravel optical characteristics such as optical path diagrams and aberrations, which are generally not visible, and explain the taste and descriptive performance of lenses in a deep and gentle manner.

Now, please enjoy the special information that you can read only on this blog in the world.

Overview

This article provides a comparative analysis of the performance of two SONY 35mm large-aperture lenses: the SONY FE Distagon T* FE 35mm F1.4 ZA, released in 2015 for E-mount mirrorless SLRs, and the SONY FE 35mm F1.4 GM, released in 2021 For a detailed analysis of each lens, please refer to the respective section of the report.

Please refer to the respective articles for a detailed analysis of each.

 See also: SONY Distagon T* FE 35mm F1.4 ZA

 Related article: SONY FE 35mm F1.4 GM

First, let's take a brief look at the lineage of the world's first 35mm large-aperture F1.4 lens with auto focus, which started with MINOLTA. Here is a list of 35mm F1.4 lenses for the α camera in chronological order of release, up to the lenses released by Sony, which was transferred from Minolta.

  1. 1987 MINOLTA AF 35mm F1.4
  2. 2006 SONY SAL35mm F1.4G (MINOLTA)
  3. 2015 SONY Distagon T * FE 35 mm F1.4 ZA
  4. 2021 SONY 35mm F1.4 GM(this article)

The Sony FE 35mm F1.4 ZA (hereafter ZA) has been renewed after 30 years, and the Sony FE 35mm F1.4 GM (hereafter GM) has already been released.

At present (2021), both lenses continue to be sold, and it is not clear whether the release of the GM is meant as a renewal of the ZA or as a higher grade of the GM.

In terms of price, the three lenses currently on sale (2) to (4) have a "clean price difference" as if they are priced according to their grade, which seems to be a consideration to give users a wide range of choices by assuming that the three lenses will be sold together.

In this sense, the grade in terms of price would be GM > ZA, so GM would be the top grade.

The purpose of this article is to rethink which of the two lenses is in the top position in terms of performance.

Private Memoirs

This article and others, Analysis 57 through Analysis 61, were analyzed in a series of articles entitled "Free Research for the Summer Vacation of 2021".

The theme of the articles was to trace the history of the development of the 35mm F1.4 autofocus lens.

Since this article is the last in the series, I would like to use this column to record the production of the article.

First of all, we have been planning to analyze the MINOLTA AF 35mm F1.4 for some time. This lens was the world's first 35mm F1.4 lens compatible with autofocus, and yet it was an isolated lens with no comparable product for a long period of time, so I had nominated it for the analysis theme early on.

However, I had been putting it off for a long time, wondering when I should write about it, when the latest FE 35mm F1.4 GM was released by SONY, and at the same time I was able to find related patent documents.

I don't know what the future holds, but my guess is that there will be no new SONY 35mm F1.4 products for the next five years, so I was able to put this article together at the perfect time by coincidence.

Here is the list of 35mm F1.4 analysis articles starting from MINOLTA to SONY.

Now, let's move on to the main topic, "Comparison of SONY FE 35mm F1.4 ZA and GM performance".

Notes!

The following design values have been selected and reproduced from the appropriate patent literature and do not correspond to the actual product. Naturally, the data is not guaranteed, and I am not responsible for any accidents or damages that may occur by using this data.

Analysis of Design Values

Optical Path Diagram

The above figure shows the optical path diagrams of the SONY FE 35mm F1.4 ZA and GM.

Although the number of lens elements has increased with ZA having 12 elements and GM having 15 elements, the number of aspherical lenses seems to have decreased with 3 ZA elements and 2 GM elements.

Please note that the GM lenses are introduced in the individual analysis articles of each lens, but the lenses described in the patent documents are in a slightly different form from the products.

The lenses in this article are summarized assuming that the information in the patent literature is equivalent to the design value.

The ZA has a graceful and gentlemanly composition, as if it were a quintessential ZEISS lens, while the GM's composition is aggressive and very typical of SONY's pursuit of advanced technology.

Longitudinal Aberration

Graphs of spherical aberration, image surface curvature, and distortion

Spherical Aberration , Axial Chromatic Aberration

Let's look at spherical aberration. Both lenses are at the same level, but the convergence of each color at the upper end of GM's spherical aberration chart is uncanny.

The axial chromatic aberration seems to be at the same level.

Field Curvature

Looking at the image curvature, the GM has a complex and bizarre undulating shape that on average makes the entire image smaller.

It is a really bizarre characteristic.

ZA's curvature is orthodox and natural, not so inferior to GM's.

Distortion

The GM's distortion is abnormally small for a wide-angle lens.

Is the designer being bullied by his boss? The level of abnormality is a little worrisome.

Lateral Chromatic Aberration (Magnification Chromatic Aberration)

The ZA has a slight bulge in the middle of the image for magnification chromatic aberration, while the GM has a natural characteristic of slightly increasing chromatic aberration at the periphery of the image.

Transverse Aberrations

(Left)Tangential direction, (Right)Sagittal direction

Let's look at it as a Transverse Aberrations.

The sagittal aberration of GM's lens has a straight line to the edge of the image, and the so-called sagittal coma flare is close to zero in the entire image area.

Even at the ZA level, the sagittal coma flare is not large and is excellent, but the GM's correction level is out of the ordinary.

Spot Diagram

Spot Scale 0.3 (Standard)

Here are the optical simulation results, but let's start with the spot diagram.

Both lenses are not old, so they are quite competitive.

Let's take a closer look at the magnified scale below.

Spot Scale 0.1 (Detail)

The GM does not lose its circular shape when viewed on a detailed scale, while the ZA has a slightly distorted V-shape around the image height of 21mm at the corners of the image.

MTF

Maximum Aperture F 1.4

Finally, let's check the results of the MTF simulation.

The ZA also has a commendable high performance considering its large aperture specifications, but it seems to have evolved a step further from the GM. All the peaks are high and uniformity is improved.

Small Aperture F4.0

When stopped down to F4, there is little difference in performance at the center of the image, but at the periphery of the image, we can observe that the GM has a higher degree of improvement from wide open.

Conclusion

Now, when I do a comparative analysis again, I am astonished at the degree of improvement in aberration of the FE 35mm F1.4 GM.

Moreover, it seems to be slightly smaller and lighter in weight. If you simply want a high performance lens, this is the best choice.

In recent years, the 35mm F1.4 lens has become synonymous with the highest quality lenses from various companies, so I guess SONY has made it the embodiment of the highest quality that lives up to the GM name.

On the other hand, the FE 35mm F1.4 ZA is a high-performance lens that lives up to the ZEISS name and is still available today, but at a much more reasonable price.

The question of which one to buy is endless.

This article is part of a series of articles that provide a comprehensive analysis of the history of 35mm F1.4 lenses, starting with MINOLTA and continuing with SONY.

See below for related analysis articles.

Sample Picture

Example photos are in preparation.

If you are looking for analysis information on other lenses, please refer to the table of contents page here.

-MINOLTA, SONY
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