Review of Viltrox AF 20mm 1: 2.8 STM ASPH ED IF (Air, Sony FE, Nikon Z)

Navigation

1. In short
2. Main Specifications
3. Assembly
4. Focusing
5. Firmware Upgrade
6. Image quality
7. Sample Photos
8. My experience
9. Price
10. Video review
11. Results
12. User Comments
13. Add your review or question on the lens

In this review I will call the Viltrox AF 20mm 1:2.8 STM ASPH ED IF lens for short Viltrox 20 / 2.8.

It's important: This review shows the Viltrox 20/2.8 version for Sony mirrorless cameras with a mount Sony e-mount and with firmware version v1.1.2. At the same time, there is a modification of this lens for mirrorless cameras of the system Nikon Z. Also, a bayonet mount release has been expected for several years now fujifilm x.

It's important: Viltrox 20/2.8 can be found with a white body color.

In short

Viltrox 20/2.8 – a modern lens for full-frame mirrorless cameras with a bayonet mount Sony E / FE и Nikon Z. It has internal automatic focusing, works quite quietly thanks to the stepping motor of focusing. Optically balanced! Seven aperture blades, light weight (only 170 grams!), compact dimensions, complex optical scheme, and the price of Viltrox 20/2.8 is only around $ 160.

Viltrox 20/2.8 is a best seller.

It's important: when searching and choosing autofocus optics for Sony E-mount Full Frame, use these very useful links:

• All autofocus lenses for Sony E/Sony FE (original and third party)
• All autofocus lenses for Nikon Z (FX/DX) (original and third party)
• All lenses felttrox

Main technical characteristics of Viltrox AF 20mm 1:2.8 STM ASPH ED IF:

Review Instance Name	Near the front lens: Viltrox AF 28mm 1:2.8 STM ASPH ED IF IMAGE SIZE Ø43.3 Ø52mm 0.19m/0.62ft On the body: Viltrox AF 28/2.8 FE + identification plate
Basic properties	FE (Sony Full Fcopper E-mount) - designed for Sony E-mount mirrorless full-frame cameras (Sony E mount) AF (Acles Focus) - the lens supports auto focus STM (Scarpets Motor) - focusing stepper motor IF (Iinternal Focusing) - internal focus ED (Extra Low Dispersion) - low dispersion elements in the optical scheme ASPH (Aspherical) - aspherical elements in the optical design Elements with ultra-high refractive index in the optical scheme USB-port for firmware update Electronic focus ring Lens hood and soft case included Viltrox AIR – the lens belongs to the AIR lens line, which is characterized by lightness and compactness (these include models 25/1.7, 35/1.7, 56/1.7, 40/2.5, 50/2) Protective water-repellent coating on the front lens Available in two body colors Important: lens from a third-party manufacturer, which imposes some restrictions on its use
Front Filter Diameter	52 mm
Focal length	20 mm, EGF Sony E APS-C / APS-C Nikon Z (Nikon DX) is 30 mm
Zoom ratio	1 X (this is a fixed lens, it does not have a zoom)
Designed by	for Sony NEX/Sony ALPHA/Sony ILCE mirrorless cameras with E-mount (sometimes listed as FE)
Number of aperture blades	7 rounded petals
Tags	bayonet mount mark and hood mount mark
Diaphragm	F / 2.8 to F / 16
MDF	0.19 meters, maximum magnification ratio 1:5.9
The weight	157 grams according to my measurements without covers and hood (version for Sony E)
Optical design	10 elements in 8 groups. The scheme includes 2 low dispersion elements 1 ultra high refractive index element 2 aspherical elements The image of the optical scheme is clickable to enlarge
Lens hood	Bayonet type, model Viltrox PL-56
Manufacturer country	MADE IN CHINA (Made in China)
Period	from November 2023
Firmware	The lens in the review used firmware v1.1.2
Prices	View on AliExpress at the official Viltrox store

The actual aperture ratio (T-stage) is quite high, and is at the T/2.9 level.

Assembly

The lens came for review new in its original box.

Viltrox 20 / 2.8 has metal mount. The focusing ring is wide, not rubberized, plastic. The lens feels good in your hands. The Viltrox 50/2 is specially designed with a plastic housing to minimize its weight. The weight of Viltrox 20/2.8 is about 160 grams. The diameter of the front filter is only 52 mm.

The body has a bayonet mount mark and a quick-mount hood mark. The lens uses a small plastic Viltrox PL-56 hood, which should be fixed in special grooves located near the front lens of the lens. The hood can be installed in the transport mode with the back side, in this position there is practically no loss of access to the focusing ring. The front lens has a special protective covering, repelling water, dust and dirt.

The lens has a connector USB TYPE C to connect to a computer.

It's important: The lens is initialized after the camera goes to sleep and wakes up, and when the camera is turned on. During initialization, the lens changes its aperture from F/16 to the specified value. The lens also sets a certain focusing distance.

It's important: When the lens is detached from the camera, or when the camera is turned off, or when the camera is in 'sleep' mode, the aperture blades are always closed down to f / 16.

Important: Initialization takes about one and a half seconds, which makes it difficult to quickly turn on the camera and take the first photo.

Focusing

For focusing, the Viltrox 20 / 2.8 uses stepper focus motor STM (Stapping Motor). Auto Focus should work with all Sony cameras with an E / FE mount.

Very important: Viltrox 20/2.8 will only work correctly with modern cameras with a Sony E mount. Certain difficulties may arise with older models. For example, on cameras Sony NEX-F3 (2012) and Sony a3500 (2014) Viltrox 20/2.8 automatic focusing works noticeably worse. Most likely, for correct operation of Viltrox 50/2 a camera with phase focusing sensors is needed. For example, on Sony a7 The lens works correctly in photo mode.

The focusing speed is average, closer to high, quite comfortable for work. I didn't have any problems focusing on the Sony a7. After the lens loses precise focus, refocusing is performed quite quickly.

It's important: in difficult shooting conditions, as well as when shooting dynamic scenes, the focusing quality with the Viltrox 50/2 can be noticeably worse than with original similar lenses. Even in simple shooting conditions, the tenacity of autofocus with the Viltrox 20/2.8 will greatly depend on the camera used. Perhaps over time, new firmware for the lens will improve this situation.

Auto focus silent, but there is still a slight hum from the focus motor.

Lens uses electronic focus ring. Focus ring not rubberized, wide, in manual focus mode rotates approximately 270 degrees. When extreme positions are reached, the ring does not abut, but continues to rotate. Manual focus is enough conveniently. The focus ring rotates easily. I did not observe any delay (lag) when changing the direction of rotation. The electronic focusing ring is well implemented and responds more to the angle of rotation than to the speed of its rotation.

During auto focus focus ring remains stationary, however, it can be freely rotated without any effect on focus (if the normal AF mode 'Autofocus', not 'MF', and not 'DMF' is enabled in the camera menu). During manual focusing, a scale of approximate focusing distances appears on the display of some cameras.

The lens has internal focusing, the front lens remains stationary during focusing. It is possible to use various filters without any problems.

The minimum focusing distance is 19 cm.

The 'Focus Breathing' effect (changes in viewing angle during focusing) is small; when focusing towards the MDF, the viewing angle decreases.

There are no useful marks on the focusing distance, depth of field, or anything else on the lens.

Focus shift (shift-focus) was not noticed during operation and testing.

Firmware Upgrade

On the mount side, the Viltrox 20 / 2.8 has a USB port that can be used to update the software (firmware / firmware) of the lens.

The connection uses a common USB TYPE C port (many mobile phones use this). The delivery set includes such a cable. The latest firmware for the lens can be found here.

The firmware update will most likely improve the compatibility of the lens with new cameras, improve the autofocus performance, and eliminate some other disadvantages.

Important: To update the lens firmware (software):

1. Turn off the camera, detach the lens
2. Connect the lens to a computer using a USB cable. The lens should be identified as a 'Viltrox DFU' drive
3. Find the file 'DeviceInformation.txt' on this drive and check the current firmware version (the firmware version may not need to be updated)
4. Copy the firmware file to the 'Viltrox DFU' folder (file with the '.dat' resolution, which must be downloaded from the official Viltrox website). Wait for the end of copying
5. After copying is complete, the 'Viltrox DFU' drive will automatically shut down and reconnect after 5 seconds (approximately), after which you can check the current firmware version
6. Disconnect cable
7. Attach the lens to the camera
8. Turn on the camera

Image quality

The Viltrox 20/2.8 has its quirks, but is overall good.

Sharpness

• good sharpness at open aperture in the center of the frame
• very good resolution in the center of the frame is achieved after f / 4
• there is a slight drop in sharpness in the far corners of the frame
• there is a very weak coma

Distortion

• the distortion is weak but complex
• It is difficult to correct distortion manually

Vignetting

• strong vignetting at F / 2.8
• vignetting almost completely disappears at values ​​after F/8
• vignetting decreases with focus towards MDF
• vignetting is strongest when focusing at infinity

Aberration

• the lens creates a small amount of chromatic aberrations, both longitudinal and transverse
• frigging disappears after F/4

Rest

• the star ray effect is well expressed (14 rays) at apertures after F/5.6
• the lens works well in backlight, only in the most difficult conditions can you get flares that significantly spoil the picture
• the bokeh is nice

Full Frame Photo Samples

Camera used Sony a7 (24 MP Full Frame Exmor HD CMOS sensor) and camera Sony a3500 (20 MP Sony Exmor APS-C HD CMOS sensor).

• Original photos in RAW format (Sony '.ARW' 12-bit compressed, only Sony a7) can download / watch this link (Google Drive, 50+ photos).
• Photos in JPEG format ('.JPG' with Sony a7 и Sony a3500) can download / watch this link (Google Drive, 70+ photos).

My experience

Viltrox 20/2.8 is a simple and straightforward ultra-wide-angle lens. Balanced, lightweight and affordable. Personally, I was a little disappointed with the lens's vignetting and complex distortion, which are very important qualities for an ultra-wide-angle lens.

There are not many similar lenses out there: Tamron 20mm F / 2.8 Di III OSD M1: 2 (Model F050), ZEISS Distagon 2.8/18 T* (Batis 2.8/18), Samyang Remaster Slim 21/3.5, Samyang AF 18 / 2.8 FE, the rest are either a step brighter or have a focal length of 24-28 mm. At one time, lenses of the 20/2.8 class were more common than now (remember at least Nikon AF Nikkor 20mm 1: 2.8D). Viltrox 20/2.8 is the most affordable such autofocus ultra-wide lens for Sony FE/Nikon Z.

Viltrox 20 / 2.8 also great for cropped cameras. Can be an alternative for cropped Sony E 2.8 / 20 (SEL20F28, about $350). Looks good on my tiny camera. Sony NEX-F3.

The entire Viltrox lens series deserves due attention.

Price

The price for Viltrox 20/2.8 is about 160 dollars, which is a very attractive offer. View prices for Viltrox 20/2.8 on Aliexpress you can follow this link from the official Viltrox store.

Video review

Results

Viltrox 20/2.8 – lightweight, compact, with a stepping motor for focusing and good optical performance.

10 main advantages:

1. low cost (about 160 $)
2. good assembly, metal bayonet mount, bayonet hood included, protective coating of the front lens
3. light weight
4. compact sizes
5. stepping focus motor fast enough
6. internal focusing, fixed focus ring during auto focus
7. electronic focusing ring, continuous manual focus control
8. USB port for firmware upgrade
9. modern complex optical design, which includes 8 special optical elements
10. high resolution across the entire frame starting at F/5.6

10 main disadvantages:

1. there are no additional tags (depth of field, focusing distance, etc.)
2. there is no rubber seal for the bayonet mount (although it is stated that the lens is protected to a certain extent)
3. no AF/MF focus mode switch
4. no aperture control ring
5. focusing does not work well with older Sony XEX/ALPHA cameras without phase detection focus sensors
6. mediocre aperture (in the background Sony FE 20/1.8G, Sigma 20/2C DN, Tokina FE 20/2)
7. only 7 aperture blades
8. sometimes there is an excessive amount of glare when working in difficult backlighting
9. complex distortion
10. strong vignetting at F / 2.8

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Material prepared Arkady Shapoval.