Review: Viltrox PFU RBMH 20mm f1.8 ASPH (Sony FE)

The Viltrox PFU RBMH 20mm f1.8 ASPH is an affordable ultra-wide angle lens for Sony E Mount.

Up until now, Viltrox was known primarily for their camera accessories and lens adapters, so our interests were piqued when we were first introduced to the Viltrox PFU RBMH 20mm f1.8 ASPH lens during PhotoPlus last year. After spending some brief time with the fully manual ultra-wide angle lens on the convention floor, we came away intrigued and were eager to get a review sample in for testing. With their 20mm f1.8, Viltrox is offering Sony mirrorless shooters a value proposition in the form of an affordable ultra-wide housed within a metal body that is both well built and produces excellent images. Read on to find out how well the freshman lens maker fared.

Pros and Cons


  • affordably priced
  • solid metal construction with smooth tactile feedback
  • beautifully creamy bokeh
  • excellent image quality with minimal distortions
  • supports filters when using the dedicated lens hood


  • lacks weather sealing


Tech Specs

Tech specs for the Viltrox PFU RBMH 20mm f1.8 ASPH (Sony FE) were taken from Viltrox’s marketing pamphlet

FocaI Length 20 mm
Aperture f1.8 – f16
Aperture Blades No. 14
Camera Mount Sony FE-Mount
Format Compatible Frames Full Frame
Shooting Distance 0.25 m (9.84″) – ∞
Field Angle (Diagonal / Horizontal / Vertical) 94°12′ / 75°22′ / 56°31′
Focus Mode MF (IF)
Image Field Diameter 43.2 mm (1.7″)
Close Range Coverage 199 x 299 mm (7.8 x 11.77″)
Image Ratio at Min. Distance 1:8.3
Lens Structure 12/9
Flange Distance 18 mm (0.71″)
Pupil Position (Image Surface Benchmark) 87.6 mm (3.45″)
Auto Focus – –
Image Stabilization – –
Auto Iris – –
EXIF Information – –
Filter Specification M82 x 0.75
Rotation Angle of the Focusing Ring 148.5°
Max. Diameter 76.8 mm (3.02″)
Diameter of the Focusing Ring 72 mm (2.83″)
Length (with Lens Cap) 123 mm (4.84″)
Length (without Lens Cap) 102 mm (4.02″)
Weight 775 g (1.71 pounds)



Here’s the Viltrox PFU RBMH 20mm f1.8 ASPH, seen here with the tulip style lens hood attached. When you’ve got the lens in your hands, it definitely feels well put together and very solid, and weighs in at a considerable 1.71 pounds, thanks to it’s mostly all metal and glass construction.

Two separate lens hoods are included with the Viltrox 20mm f1.8, a short tube style one as well as a tulip style one. The tube style lens hood (AL-08A) is designed to work with 82mm filters while the tulip style lens hood (AL-08B) does not support the mounting of filters.

Here’s what the Viltrox PFU RBMH 20mm f1.8 ASPH looks like with the tube style lens hood attached.

Moving towards the front of the Viltrox 20mm f1.8, here’s what the lens looks like when the front lens cap is attached. Note that you will only be able to attach the lens cap onto the petal style lens hood (AL-08B), as the rear opening of this lens cap is smaller than the circumference of the tube style lens hood. This is certainly something to keep in mind if you plan on using filters with this lens and want to keep the filter protected.

Here’s a look at the front end of the Viltrox 20mm f1.8. The markings for the maximum constant aperture (f1.8), focal length (20mm), filter thread size (82mm) are etched around the convex front element and are clearly visible.

Looking at top side of the Viltrox 20mm f1.8, you will find the model number of the lens etched way up front on the lens, followed by the de-clicked manual aperture control ring, manual focusing ring, along with a depth of field scale. Thanks to their distinct differences in width, it’s very easy to differentiate the aperture control and focus rings by feel. Both rings felt very smooth when rotating, and require a moderate amount of force to rotate, with the manual aperture control ring require slightly more than the manual focus ring, further helping to differentiate the two apart.

The Viltrox 20mm f1.8 has a maximum aperture of f1.8, and can be stopped down to f16. It is capable of focusing from 0.25m all the way to infinity.

Moving towards the rear of the Viltrox 20mm f1.8, here’s the mount covered with a Viltrox branded rear lens cap.

The Viltrox 20mm f1.8 is a truly manual lens in every sense of the word, something that becomes very apparent once we remove the rear lens cap to reveal the back side of the lens. You will clearly notice the absence of any electronic contact points whatsoever on the Viltrox PFU RBMH 20mm f1.8 ASPH’s mount, meaning that not only will you need to manually make all of the adjustments when using the lens, but you will also need to record your camera settings elsewhere if that’s something that you’re in the habit of doing. You also won’t see any rubber gaskets on this end of the lens, as the Viltrox 20mm f1.8 is not weather sealed.

“If you happen to be allergic to manual controls, however, this is obviously not the right lens for you.”

Build Quality

The Viltrox PFU RBMH 20mm f1.8 ASPH is a solid ultra wide angle lens that feels well put together, thanks to its robust metal exterior. The manual aperture control ring and manual focus ring both feel buttery smooth when rotating, with just the right amount of resistance. The aperture control ring is also de-clicked, so video shooters will appreciate that as well. The only drawback to this lens is that it lacks weather sealing of any kind, so photographers looking for an ultra wide angle for their outdoor work will want to look elsewhere unless they happen to live in the desert and rarely encounter precipitation of any kind.


Ease of Use

If you are familiar with manual glass, the Viltrox PFU RBMH 20mm f1.8 ASPH is honestly pretty straight forward to use. Simply remove the front and rear lens caps, mount the lens onto your E mount camera body, and you’re ready to start shooting. If you happen to be allergic to manual controls, however, this is obviously not the right lens for you.


Image Quality

You’ll find lots to love about the images created with the Viltrox PFU RBMH 20mm f1.8 ASPH. Objects in focus are tack sharp, falling off nicely and gradually as you move towards the out of focus elements within your frame. When shooting with the Viltrox 20mm f1.8, center sharpness is excellent throughout the aperture range, but corner sharpness leaves something to be desired if you’re shooting wide open. If corner to corner sharpness is your thing, you’ll want to stop down a bit. We found f8-f11 to be the sweet spot with the review unit that we received.


For the most part, the Viltrox PFU RBMH 20mm f1.8 ASPH renders some beautifully creamy bokeh, thanks to its 14 bladed round aperture design. You’re going to get some lovely circular bokeh balls around the center of your frame, and as you move towards the sides of your frame, you will notice the bokeh balls beginning to stretch out slightly.

Chromatic Aberration

You may notice some color fringing as well as slight onion rings within the bokeh balls on occasion if you’re pixel peeping, but you really shouldn’t be doing anyway. You might also detect some flaring if there happen to be light sources aimed at your lens, but to be perfectly honest, this gives the Viltrox 20mm f1.8 some character. We also didn’t find any significant distortion despite the lens’ ultra-wide focal length, and those can be easily corrected during post-processing anyway. All in all, you’re going to be pretty pleased with the quality of the images shot with this lens.

Color Rendition

During our testing, we were able to produce pretty color accurate images using the Viltrox PFU RBMH 20mm f1.8 ASPH. Shooting in custom white balance that matches the light sources in your scene will obviously give you the most consistent results.

Additional Image Samples




In some ways, the Viltrox PFU RBMH 20mm f1.8 ASPH reminds us of the Rokinon 20mm f1.8, albeit in a more robust metal body. Just like the Rokinon, the Viltrox 20mm f1.8 is an affordable, fully manual piece of glass that lacks any onboard electronics or weather sealing. The absence of an autofocus mechanism shouldn’t really deter anyone, however, as the 20mm focal length is traditionally the realm for landscape and architectural photography where autofocus is rarely necessary anyway. Although if you plan on using this lens in places that get hit with a lot of precipitation, you’ll most likely want to put your camera inside some sort of rain cover so no water gets in between the lens and the mount. The Viltrox PFU RBMH 20mm f1.8 ASPH is an excellent effort by the accessories turned lens manufacturer that is sturdily built, competitively priced, and capable of producing some outstanding images.

The Viltrox PFU RBMH 20mm f1.8 ASPH earns four out of five stars. You can pick one up for yourself here