This page contains reviews of 50mm F2 DG DN Lens.
Lens Summary
| Price | It's a little expensive, but it's worth it. |
| Size | Just the right size |
| Weight | Just the right weight |
| Ease of use | Not the best, but good |
| AF performance | Other than focus breathing, everything is fine. |
| Resolution performance | Excellent long-distance resolution |
| Bokeh | Smooth background blur over a wide area |
| chromatic aberration | Fairly good correction |
| distortion | calm barrel-shaped |
| coma aberration | Good correction status |
| Vignetting | Slight effects |
| flare resistance | Very good |
| Overall evaluation | The best choice as a 50mm f/2 |
Evaluation：
The best 50mm F2 with a superbly made lens barrel and an optical system with excellent optical performance. Although it does not have perfect optical performance, it is an interesting lens that comes alive with a good “flavor (individuality)”.
Foreword
- Release Date:2023.04.03
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A standard fixed focal length lens for the Sony E and Leica L mounts, to be released in April 2023. This lens belongs to the Sigma “I Series”, and is the second lens to cover the standard range after the “45mm F2.8 DG DN”. The series is characterized by its high-quality metal barrel, including the hood, and the optical system is typical of the Contemporary line (excellent in terms of versatility and portability).
specifications
| lens mount | E/L |
| Supported sensor size | Full frame |
| focal length | 50mm |
| Lens construction | 11 lenses in 9 groups |
| Aperture | F2-F22 |
| Aperture blades | 9 |
| Minimum focusing distance | 0.45m |
| Maximum magnification | 1:6.9 |
| Filter diameter | 58mm |
| image stabilisation | - |
| Teleconversion lens | - |
| Coating | SMC/Fluorine coating |
| Size | φ65.8×76.9mm |
| Weight | 340g |
| weather sealing | Sealing at the mount |
| AF | Stepping motor |
| Aperture ring | Support |
| Other controls | AF/MF switch |
| Accessories | Magnetic cap and hood |
Lens Review
Appearance and operability
Boxes and accessories
The simple design, based on black and white, is typical of the Sigma Global Vision (SGV) series. Information such as the lens name, filter size, compatible mount and accessories is displayed in a stylish way. The three-digit number displayed in the top right is the edition number, and uses the last three digits of the year in which it was released. (This lens was released in 2023, so it is “023”)
Cardboard is used for the partitions, and there is no cushioning material. As this is not an Art or Sports line product, the Sigma-made lens case is not included.
In addition to the lens itself, a metal lens hood, lens cap, and magnetic metal cap are included.
Appearance
Although this lens belongs to the Contemporary line, it has a high-quality exterior made entirely of metal, as you would expect from the I Series. It uses metal parts for the aperture and focus rings, with only a few plastic parts. It doesn't have the sleek design of Sony's ZA lenses, but it's still good. The shiny center ring is a decorative part and doesn't have any particular meaning. However, you can feel it through the viewfinder, so it's useful as a point to rest your left hand on when you don't want to touch the focus or aperture rings.
At first glance, the exterior markings look like they have been printed, but when you touch them, they feel like they have been engraved with slight bumps and hollows. There is information such as the country of manufacture (Japan), edition number, and serial number.
Hands-on
It's a little bigger and heavier than a 50mm F2 lens, but it's still within acceptable limits. It has a good weight to it, and it stimulates the joy of ownership. The design of the lens may be a matter of personal taste, but I personally like it. The exterior has a matte finish that makes it less likely to get scratched or fingerprinted. However, the glossy decorative ring is more likely to get fingerprinted.
Front and back
The front of the lens also uses a metal part. It has a unique shape to fit the dedicated magnetic metal cap. Other companies sometimes print the lens name or filter size on the front, but the front of Sigma lenses is simple. I think Sigma's design is preferable because white printing can sometimes reflect light.
The filter size is compatible with 58mm diameter. There are many E-mount lenses, but few of them are 58mm diameter. The only I Series lens that uses 58mm diameter is the 35mm F2. You will need to get C-PL and ND filters separately or use step-up rings.
The brass lens mount is secured with four screws. There is a simple dust- and splash-proof seal around it. The seal is a little tight when attaching it to the camera. The area around the rear lens is painted black to prevent reflections, and there appear to be no parts that reflect unnecessary light.
Focus ring
The metal focus ring is located at the tip of the lens. Compared to Sony's genuine lenses, it has a more resistant feel and is more similar to Panasonic LUMIX S lenses. The response of the Sony E-mount is “non-linear”, and the distance the focus moves changes depending on the rotation speed. Even so, when rotated quickly, the stroke for operating the entire range is long at about 180 degrees. When rotated slowly, fine adjustment is possible with a stroke of 2 to 3 rotations or more.
Aperture ring
It is equipped with a solid aperture ring with a click. It requires more force to rotate than the focus ring, so there is no risk of accidental operation. It is a pleasant and easy-to-use feature for still images. However, unlike the Art series and Sony genuine lenses, the click cannot be released. Because the resistance of the click is strong, if you operate the aperture ring during video recording, there is a high possibility that the frame will be out of focus or an operation sound will be generated.
Switch
The AF/MF switch is located on the left side of the lens. Generally, the switch is parallel to the optical axis (sliding back and forth), but this lens has a design that switches it up and down. When in AF mode, the blank area is displayed in white, making it an effective design. It is positioned and designed to be easy to operate with the left thumb.
Lens Hood
A metal lens hood is included that gives the same quality feel as the main body. It doesn't have the same stylish look as the Sony ZA lens, but considering the design of the main body and the company's own camera (fp), this may be the best solution. The lens hood can be attached upside down, but it does not allow access to the focus ring.
Example of use
Attached to the α7R V. It's a little large for a 50mm F2 lens, but the balance is good. It's not front-heavy, so it's easy to hold with one hand. There is enough space between the grip and the lens, so it's easy to operate the focus ring and aperture when shooting. This is a lens that provides a high-quality shooting experience.
AF・MF
Focus Speed
A stepping motor is used to drive the focus lens. It operates at a speed that can be considered sufficiently fast. As with third-party lenses, the operating speed differs between AF-S and AF-C, and AF-C is recommended if you want to emphasize instantaneous response. It also achieves smooth and quiet AF that is also suitable for video recording.
Breathing
Focus breathing refers to the change in the angle of view depending on the focus position.If the change in angle of view is significant, the field of view will expand or contract during focusing, potentially causing distractions and affecting autofocus stability. Ideally, it is better to have no focusing breathing. In order to check the effects of breathing, we took the following photos with the lens stopped down to the minimum aperture, at the minimum shooting distance and at infinity.
Many standard lenses have noticeable focus breathing, and this lens is no exception. The change in angle of view is noticeable at the minimum shooting distance and at infinity. Unlike Sony genuine lenses, this lens does not support focus breathing correction, so it is difficult to deal with the change in angle of view.
AF accuracy
No problems as long as it is used in combination with the α7R V or α7 IV.
MF
As mentioned above, the long-stroke focus ring allows for highly precise manual focusing. On the other hand, it is not suitable for situations where quick focusing is required, such as when taking snapshots. In such cases, you will need to switch to AF.
Resolution Chart
Test conditions
- Camera body:A7R V
- Interchangeable lens:50mm F2 DG DN｜Contemporary
- Pearl Optical Industry Co.
‘[HR23348] ISO12233-compliant 8K resolution test chart (for still cameras)’ - Olympus HYRes 3.1 analysis software
- The lighting environment is constant indoors.
- Tripod, self-timer 10 seconds, electronic shutter
- RAW output
- ISO 100
- RAW development in Adobe Lightroom Classic CC
・Sharpness: Off
・Noise reduction: Off
・Chromatic aberration correction: Off - Focus on each point to be analysed and take a picture
(image plane curvature is difficult to measure at close range, so check at infinity) - Note that this is a test at close range (infinity may be even better).
- If you adjust the sharpness when developing JPEG or RAW images, the values may improve. Please note that the values given here are the ‘minimum values’.
Test results
In the distant resolution test, it produced excellent results similar to those of Art and GM, but its performance deteriorated significantly when taking close-up photos. In particular, the periphery and corners become quite soft, so you need to be careful. Closing the aperture gradually improves the results, but the corners never catch up with the periphery.
Centre of frame
The aperture is slightly soft, but you can get good results compared to the edges and corners. The contrast improves when you narrow the aperture, and it peaks at F4 to F8. After F11, you need to be careful because the effects of diffraction rapidly decrease.
Middle of frame
Compared to the center, the contrast is maintained, but the resolution performance is a little weak. It gradually improves when you stop down, but the improvement speed is slow until it reaches the peak at F8.
Four corners of frame
Performance is even lower than in the surrounding area. F2 is not measurable, and the values are also quite low after F2. Results are a little more stable after F5.6, but there is no improvement even if you stop down further.
Sample
far-field resolution
Test environment
Date: 2023-04-21: Cloudy, light breeze
Camera: α7R V
Tripod: Leofoto LS-365C
Head: SUNWAYFOTO GH-PRO II
Exposure: Aperture priority AE ISO 100
RAW: Adobe Camera RAW
Sharpness off
Noise Reduction off
Lens correction off
Test results
Good resolution performance is achieved across the entire frame from the maximum aperture of F2. There is no extreme drop in image quality towards the edges or corners, and contrast is also maintained well. It appears that spherical aberration, axial chromatic aberration, and even magnification chromatic aberration and coma aberration are all optically corrected to a high degree. When the aperture is closed, the slight axial chromatic aberration that remains converges, and the lens demonstrates its peak performance with sharp, high contrast images. Performance is maintained up to around F8, and after F11, it gradually decreases due to diffraction.
Centre of frame
Although the contrast and color saturation of the details are slightly reduced at the maximum aperture of F2, the resolution performance is very good. If you stop down to F2.8, the contrast improves and you can get almost peak performance. It improves even more at F4, but only slightly. Peak performance is maintained up to F8, and after F11, it deteriorates due to diffraction. If you want to make the most of the 61-megapixel resolution performance, I think it's better to keep it down to around F11.
Middle of frame
Even in the peripheral areas, you can get the same excellent resolution performance as in the center at F2. If you want to get the best results, you should use F2.8 or higher, but even at F2 you can get good results.
Four corners of frame
Surprisingly, there is no significant drop in image quality even at the corners of the frame. Although typical 50mm F2 lenses that use a double-Gaussian type have a significant drop-off towards the periphery (mainly coma and astigmatism), this lens is completely free of problems from F2. If you stop down to F4, the image quality improves even further, and you can get excellent results that are on a par with the periphery. It is no exaggeration to say that this is a lens that makes the most of the 61-megapixel α7R V.
curvature of a surface
What is surface curvature?
This refers to the fact that the shooting distance at which the image is in focus differs from the centre to the four corners. For example, even if the image is in focus at a shooting distance of 1m, if the subject is moving back and forth around 1m at the edge of the frame, there is a possibility of field curvature.
Although there are few lenses that have noticeable field curvature, in recent lenses, aberration may increase and become noticeable at close distances. However, there are few opportunities to take photos of flat subjects at close range, so even if there is some image curvature, there is no need to worry.
However, if there is an effect even at infinity, you should be careful. If you are trying to achieve a pan-focus effect, for example in a landscape, there is a possibility that you will end up with an unintentional out-of-focus image. As there is no way to correct this aberration, the only way to avoid the problem is to increase the F-number to widen the depth of field.
Test results
It is a good correction, and there are no problems with shooting distant scenery.
Lateral chromatic aberration
What is lateral chromatic aberration?
A colour shift that appears mainly around the edges and corners of the frame. Unlike longitudinal chromatic aberration, the effect of correcting this aberration using the aperture is small, so it is necessary to correct it at the stage of optical design. However, it is possible to digitally correct chromatic aberration using the image processing engine built into the camera body. This makes it possible to correct chromatic aberration, which is difficult to correct optically alone, and recently, there have been lenses that prioritise the correction of other aberrations over chromatic aberration correction. In particular, mirrorless systems tend to rely on post-processing.
Test results
The correction is fairly good, but it is not perfect. There is no tendency for it to improve even if you adjust the aperture.
Longitudinal Chromatic Aberration
What is longitudinal chromatic aberration?
Longitudinal chromatic aberration is a colour shift that occurs in front of and behind the plane of focus. If the area in front of the plane of focus is mainly purple fringing, and the area behind the plane of focus has unnatural green colouring in the out-of-focus area, then the main cause is likely to be longitudinal chromatic aberration. This is more likely to occur with large-aperture lenses such as F1.4 and F1.8, and in such cases it is necessary to close down the aperture to improve the situation. It is possible to correct this using development software, but it is more difficult to process than lateral chromatic aberration, so it is best to suppress the aberration optically if possible. However, when suppressing longitudinal chromatic aberration with a large-aperture lens, the product price tends to be higher. Lenses that perfectly correct for longitudinal chromatic aberration have high contrast on the focal plane from wide open aperture, so you can expect a punchy resolution.
Test results
When the aperture is wide open, you can see a slight color cast in front of and behind the focus point. Compared to large-aperture lenses from a generation ago, the aberrations are mild, but in high-contrast situations, the slight color cast may be noticeable. Even when the aperture is narrowed down to F2.8, the residual aberrations are noticeable, so if this bothers you, you will need to narrow the aperture down to around F4 when taking pictures.
Distortion
What is Image Distortion?
Distortion refers to the phenomenon where straight lines do not appear straight on a flat surface. It is particularly noticeable when there are many straight lines, such as when there are man-made objects or a horizon in the image, and it can be divided into two types: barrel distortion, which is similar to that of a fisheye lens, and pincushion distortion, where the centre of the image appears compressed.
This is an aberration that can be corrected relatively easily, but it is difficult to manually correct distortions with complex shapes. In this case, a correction profile that matches the lens is required.
Test results
A gentle barrel shape. Although there is a tendency for lenses for mirrorless cameras to correct distortion with software to make it easier to process later, the distortion in this lens is already corrected optically. It can be used almost without any problems even without correction. If necessary, it can be corrected using a profile in the camera body or in development software.
Coma aberration
What are coma and astigmatism?
Coma and astigmatism are mainly the failure of a point of light to appear as a point of light in the four corners of the frame. For example, this can be seen in artificial lights, stars and illuminations in night scenes. Even during the day, bright point light sources such as sunlight filtering through trees can also have an effect. As this problem cannot be corrected in post-processing, it is necessary to correct it optically.
Although it can be improved by narrowing the aperture, in situations where shutter speed is important, such as night scenes and astrophotography, it is not possible to narrow the aperture, and optical correction may be necessary.
Test results
This is very good for correcting coma in this class of lens. There is almost no deformation of point light sources even in the corners of the frame, and the results are even better than those of the FE 55mm F1.8 ZA, which is in the same price range.
Spherical aberration
There is no significant difference between the bokeh in front and behind, but if you look closely, you can see that there is a difference in the outline of the bokeh. The bokeh in the background is a little smoother, while the bokeh in front is a little more solid. Although the correction of spherical aberration is not perfect, this is probably what leads to the smooth depiction of the bokeh in the background.
Foreground and background blur
What is a beautiful blur and a busy blur?
The evaluation of bokeh tends to be subjective, but I personally think that ‘soft, diffused bokeh’ is beautiful, while ‘sudden bokeh or hard-edged bokeh’ is not so good (or is a unique depiction). However, everyone has their own preferences, so there may be people who prefer the opposite. For reference, here are some examples of ‘blurred bokeh’ and ‘hard-edged bokeh’. The difference in the tendency of the depiction is mainly due to the state of correction of spherical aberration, and when the bokeh on either side is soft, there is a tendency for the bokeh on the other side to become hard.
Back Blur
The background blur is soft and diffused, while the foreground blur is hard and two-lined. This is the same tendency as other I Series cameras, and the important background blur is soft, so it is positively evaluated. If there is one disappointing point, it is the influence of axial chromatic aberration, and in scenes with high contrast, the coloration of the blur may stand out badly.
Front Blur
Bokehball
Effects of Vignetting and Spherical Aberration
If vignetting is strong, the bokeh at the four corners of the frame will be elliptically deformed or partially missing. The only way to solve this problem is to close down the aperture. However, closing down the aperture will make the bokeh smaller and in some cases the shape of the aperture blades may become visible, so it is necessary to compromise on the amount of vignetting depending on the situation.
If the amount of vignetting is small, it is possible to get a circular bokeh from wide open to the four corners. Ideally, a lens with little vignetting is preferable, but to eliminate it, it is necessary to fundamentally increase the size of the lens. There is a need to strike a balance between portability and cost, so some kind of compromise is necessary.
If the correction of spherical aberration is not perfect, there will be a difference in the depiction of the bokeh in front and behind (as shown in the review of bokeh in front and behind). In this case, one side will have a smooth depiction with blurring, while the other side will have a hard depiction like double-line bokeh.
Test results
There is some distortion towards the corners due to the effect of vignetting, but it is not particularly noticeable for this class of lens. The effect of vignetting can be avoided almost completely by stopping down to F2.8. Although this lens uses aspherical lenses, the inside of the bokeh is smooth and beautiful. There is almost no concentric irregularity.
Sample of a boke
Close range
When shooting close-ups, you can get a smooth, blurred background blur, probably due to the influence of spherical aberration. The background appears to dissolve more than the “F2.0” value suggests, as the edges are weak and the background is blurred.
Short range
Even if the shooting distance is a little longer, the smooth and soft depiction continues. The negative effects of chromatic aberration, astigmatism, and coma aberration are not noticeable, and the overall texture is similar to the higher-end “Art” and “G Master” models.
Medium range
Even when the shooting distance is even longer, the texture is good right up to the corners of the frame.
Portrait
The following are the results of taking pictures of a tripod that is 170cm tall while changing the distance and aperture.
Even if you put your whole body in the frame, you can still get a blur that separates the subject from the background. The slight blur in this case is smooth and beautiful for a 50mm F2 lens. Although the depiction of the periphery is a little rough, it is better than a low-priced 50mm F1.8 lens. The depiction in the center is also good compared to F1.4 lenses such as the Art and G Master. However, the effect of aberration seems to be a little stronger in the periphery.
Vignetting
What is vignetting?
Unnatural drop in light intensity around the frame.
The light intensity is lower than in the central area, and there is insufficient exposure in the four corners of the frame. This mainly occurs with large-aperture lenses and wide-angle lenses.
Although this is a phenomenon that can be easily corrected using software, it is necessary to be careful about the fact that it can cause noise, as the insufficient exposure is covered by post-processing correction (sensitization). In particular, when using high sensitivity for nightscape or starry sky photography, there is a possibility that noise will appear strongly.
Minimum focusing distance
A gentle reduction in light occurs throughout the image when the aperture is fully open. Closing the aperture by one stop greatly improves the effect, so if you are concerned about this, it is a good idea to use an aperture of F2.8 or later.
Infinity
Compared to the minimum shooting distance, there is a strong reduction in light. Closing the aperture will improve the situation, but to eliminate it, you will need to close the aperture to F5.6.
Backlight resistance, sunstar
centre
Even when exposed to a strong light source from the center, flare and ghosting are well suppressed. Although the hidden ghosting becomes apparent when the aperture is narrowed, it is better than the Sony FE 55mm F1.8 ZA.
corner
Good backlight resistance even when the light source is placed in the corner of the frame. Ghosting is well suppressed across the entire aperture range. As expected, it is better than Sony, with suppressed flare and high contrast.
Sunstar
The first streaks of light begin to appear at F2.8, but they become clear only at F8 and above. They become sharp at F11 to F22, and considering the balance with diffraction, F11 to F16 is recommended. The beautiful streaks are almost equivalent to the FE 55mm F1.8 ZA. However, the sharpness at F8 is better with the Sony ZA.
Summary
Good points
High-quality all-metal lens barrel and hood
Dust- and splash-proof
Easy-to-use focus and aperture rings
Fast and quiet autofocus
Very good long-distance resolution from f/2 to the corners
Mild magnification chromatic aberration
Smooth background blur
Beautiful bokeh even at long shooting distances
Mild barrel distortion for a mirrorless camera
Acceptable vignetting
Good correction of coma
Good resistance to backlighting
Beautiful light streaks
It has a very well-rounded high optical performance for a 50mm F2 class lens. In the distance, you can get sharp results across the entire frame from F2, and the coma and lateral chromatic aberrations are mild, and the effect of vignetting is not noticeable.
At first glance, it seems to be a description of the “honor student” type, but when shooting close-ups, the “flavor of the lens” due to residual aberration (depending on the fluctuation) is left. The smooth and soft background blur is extremely attractive. Chromatic aberration and distortion are well suppressed, so there is little dependence on post-processing, which is also good.
Bad points
No click release function on the aperture ring
Focus breathing is noticeable
Optical performance in the periphery and corners noticeably deteriorates at close distances
Slight influence of axial chromatic aberration remains
Hard front bokeh
Slightly expensive for a 50mm F2 lens
Overall, this lens is good, but when taking close-up shots, the resolution performance of the periphery and corners of the image will decrease significantly. If you want to get sharp results overall, you will need to adjust the aperture. The biggest drawback to be aware of is the large change in angle of view when focusing, and the fact that, as a third-party lens, it is not compatible with the camera's correction function.
Conclusion
It has an exquisite balance that retains its “flavor” despite its excellent optical performance. It is the best choice for an E-mount lens in the 50mm F2 class, and although it is a little expensive, it is well worth considering. Considering the excellent lens barrel and lens hood, which are typical of the I Series, you won't feel that the price is too high for this lens.
Its closest rival is the Sony Sonnar T* FE 55mm F1.8 ZA. Its stylish design and unique rendering are a must-see. Although it does not have the same excellent optical performance as Sigma, it does produce punchy results with good contrast and high sharpness.
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