Back in 2021, Sony introduced its fastest lens, the Sony 50mm f/1.2 GM lens. Today Sigma decided to match that offering with its own 50mm f/1.2 Art lens. We had this lens for less than a week which is not enough time for a full review so instead we will be doing our hands-on talk review with our colleague photographer Matan Sharon who
Special thanks to our colleague wildlife and nature photographer Matan Sharon for his help on this video
you can find more from Matan on Matanwildphotography.com
Optical Design
The Sigma has 17 elements in 12 groups with 4 aspherical elements.
The Sony has 14 Elements in 10 Groups (3 XA elements).
Materials
The Sigma feels robust with what seems like light metal and composite material.
The Sony is very well made like the rest of the modern GM lenses with composite materials.
Interesting curiosity – both lenses have a very clear element of movement when they are shaken.
The ART 50mm f/1.2 Sigma lens
Size and weight
Both lenses are relatively compact for f/1.2 glass. The sigma is a tiny bit longer at 12cm (just over 4.5”) compared to 11.5cm (4.5”) of the Sony. On the plus side, the Sigma is about 1 cm narrower (just over 7cm) compared to the Sony.
The Sigma is also surprisingly lighter at just over 750g vs. around 800g of the Sony with caps.
Rings
Both lenses include a front focus and narrower aperture rings near the back of the lens. However, the Sigma has a wider focus ring and a wider aperture ring. The focus ring on the Simga also has much more resistance compared to the Sony.
The Aperture ring on both lenses feels very similar in terms of smoothness when set to the de-click mode which both lenses include.
Buttons and switches
The Sigma includes all the recent options that you can find on modern Art lenses including AF/MF, focus hold button, de-click, and aperture lock. The Sony is similar except for an aperture lock switch which is missing and was added to the more recent 50mm f/1.4 GM.
All modern buttons and switches
Sealing
Both lenses are moisture and dust resistant according to their manufacturers.
Mount
The Sigma comes at the moment in an L mount and an E mount while the Sony only comes in an E mount.
Hood
Both lenses come with hoods. The Sony has a 4.5cm round (flat) hood while the Sigma has a longer 6cm long petal hood. Both have a release bottom but the Sony has a rubber front for protection.
Aperture
The Sony has 11 aperture blades.
The Sigma has an impressive 13 aperture blades (we will see how this affects the bokeh later on)
Filter
Both the Sigma and Sony have a 72mm front filter.
Performance
Focusing
We tested the AF on both lenses and while both are fast and silent and do a very good job on stationary and slow-moving subjects, there is a big difference between the two when it comes to tracking fast-moving subjects.
In our testing on the Sony A1, the Sigma was able to get between 5-7 out of 10 images in focus when trying to track a running person (toward the camera). This is a difficult task, however, Sony was able to get 10 out of 10 consistently so it is certainly doable, and the main difference that still exists between first and third-party lenses is in our view.
We also tested how both lenses behave in video and they both seem to focus well (at least on a regular interview setup, the video above was shot with both the Sony and Sigma wide open and both did not miss focus).
We also tested if any of the lenses have Linear focus (basically if they can return to the same focus position when turning the focus ring at different speeds). Sadly both can not (the Sigma L version might be able to do that with some cameras but we could not test that).
Image stabilization
Both lenses do not include optical image stabilization.
Sharpness
We tested the sharpness of both lenses using our special large professional Imatest high-end chart on our Sony A7R V.
Please note that we triple-tested the results below, especially the corners of the Sony 50mm, and got the same results (it is always possible that our test 50mm f/1.2 Sony lens is a less-than-optimal copy).
Sharpness test in the center – top left Sigma 50mm @f/1.2, top right Sigma 50mm @f/1.4, bottom left Sony 50mm @f/1.2, bottom right Sony 50mm @f/1.4
Sharpness test in the corner – top left Sigma 50mm @f/1.2, top right Sigma 50mm @f/1.4, bottom left Sony 50mm @f/1.2, bottom right Sony 50mm @f/1.4
Sharpness test in the center – top left Sigma 50mm @f/2.8, top right Sigma 50mm @f/4, bottom left Sony 50mm @f/2.8, bottom right Sony 50mm @f/4
Sharpness test in the corner – top left Sigma 50mm @f/2.8, top right Sigma 50mm @f/4, bottom left Sony 50mm @f/2.8, bottom right Sony 50mm @f/4
Close up performance
The Sigma has an official close-up distance of 40cm and in our test – (we are not sure of the macro magnification ratio).
The Sony has the same official minimum close-up distance of 40cm with a maximum magnification of 1:5.8 but in our test when used in MF the Sigma was able to focus a few centimeters closer (although its official macro magnification is only 1:6.2).
Both lenses seem to perform quite well at their minimum focus distance in terms of sharpness as can be seen in the images below even wide open.
Close-up sharpness test, center – top left Sony 50mm @f/1.2, top right Sony 50mm @f/1.4, bottom left Sigma 50mm @f/1.2, bottom right Sigma 50mm @f/1.4
Close-up sharpness test, corner – top left Sony 50mm @f/1.2, top right Sony 50mm @f/1.4, bottom left Sigma 50mm @f/1.2, bottom right Sigma 50mm @f/1.4
Breathing
While the Sony has breathing compensation with supported Sony cameras (on its own it has quite a bit of breathing), the Sigma has surprisingly very little breathing from what we have seen in our test (see video above).
Chromatic aberrations
The Sigma seems to have some very little longitudinal CA in our testing. However, we did see some CA in actual high-contrast shots (see below).
Our CA test – top left Sigma 50mm @f/1.2, top right Sigma 50mm @f/1.4, bottom left Sony 50mm @f/1.2, bottom right Sony 50mm @f/1.4
CA in an actual shot (300%)
Flare
Both the Sony and Sigma seem to perform fairly well against bright light sources (and very similarly to each other) as you can see in our video.
Vignette
The has a lot of vignette wide open but far less so at f/2.8 and it is almost completely gone at f/4.
With the in-camera correction turned off the Sony has a ton of vignette wide open; it clears up fairly well between f/2.8 and f/4. The Sigma seems better on this front but you are going to have the corrections on in most cases anyway.
Vignette test – top left Sony 50mm @f/1.2, top right Sony 50mm @f/1.4, bottom left Sigma 50mm @f/1.2, bottom right Sigma 50mm @f/1.4
Barrel distortion
Both lenses seem to suffer from a slight pincushion distortion when the in-camera corrections are turned off. The Sigma more so than the Sony.
Geometric distortion Sigma on the left Sony on the right
Bokeh
The bokeh circles of both lenses are basically the same. The Sony circles are fairly round and clean in the center and more oval in the corners wide open.
Bokeh test – top left Sony 50mm @f/1.2, top right Sony 50mm @f/1.4, bottom left Sigma 50mm @f/1.2, bottom right Sigma 50mm @f/1.4
Sample images
We had less than a week with the Sigma but here are a few images we shot with the lens on both the A7R V and Sony A1 (we did not edit any of the images aside from cropping/reducing their size for web use).
Conclusion
We are very impressed with the new Sigma 50mm f/1.2 DG DN Art. This lens performed extremely well, it is very compact and lighter than the Sony 50mm f/1.2, includes all the latest features (even an Iris lock which the Sony lacks), and to our surprise is even sharper than the Sony in the corners.
There is hardly anything bad to say about this lens besides its AF when tracking fast-moving subjects where the Sony remains the superior option.
You have to decide for yourself how much this single aspect of the lens is worth to you and if you are mostly into portraits with stationary or semi-stationary subjects the Sigma should be a great option.
Choose your weapon!
Pricing
The Sony currently sells for around $1900. The Sigma will start selling in April 2024 for $1400.
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Iddo Genuth 
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