What's the difference between the Voigtländer Ultron 27mm F2 X and the Viltrox Viltrox AF 33mm f/1.4?

The Ultron 27mm F2 X leads on a lighter 120g body, a more compact 23.5 mm barrel, closer 0.25 m focusing. The Viltrox AF 33mm f/1.4 leads on a brighter f/1.4 maximum aperture, autofocus at all, where the Ultron 27mm F2 X is manual focus only.

Which is smaller, the Voigtländer Ultron 27mm F2 X or the Viltrox Viltrox AF 33mm f/1.4?

The Ultron 27mm F2 X is the smaller, lighter lens at 120g and 23.5 mm long, versus 270g for the Viltrox AF 33mm f/1.4.

Which is faster, the Voigtländer Ultron 27mm F2 X or the Viltrox Viltrox AF 33mm f/1.4?

The Viltrox AF 33mm f/1.4 is the faster lens at f/1.4, against f/2 for the Ultron 27mm F2 X — brighter in low light and able to throw the background further out of focus.

Voigtländer Ultron 27mm F2 X vs Viltrox Viltrox AF 33mm f/1.4: full comparison

The Ultron 27mm F2 X leads on more of the measurable specs, but the Viltrox AF 33mm f/1.4 counters on a brighter f/1.4 maximum aperture and autofocus at all, where the Ultron 27mm F2 X is manual focus only.

Read the full Ultron 27mm F2 X review →Read the full Viltrox AF 33mm f/1.4 review →

The short version

The Voigtländer Ultron 27mm F2 X and Viltrox Viltrox AF 33mm f/1.4 are two X-mount primes at different focal lengths — the Ultron 27mm F2 X (40mm equivalent) and the Viltrox AF 33mm f/1.4 (50mm equivalent). The Ultron 27mm F2 X is the newer design, from 2023.

On the spec sheet the Ultron 27mm F2 X pulls ahead with a lighter 120g body, a more compact 23.5 mm barrel, and closer 0.25 m focusing, plus a couple of smaller edges.

The Viltrox AF 33mm f/1.4 answers with a brighter f/1.4 maximum aperture and autofocus at all, where the Ultron 27mm F2 X is manual focus only.

So which one? Start with the focal length you actually want to shoot: the 40mm-equivalent Ultron 27mm F2 X or the 50mm-equivalent Viltrox AF 33mm f/1.4. Once that's settled, Ultron 27mm F2 X has the edge on the specs above.

Where the Ultron 27mm F2 X wins

+a lighter 120g body
+a more compact 23.5 mm barrel
+closer 0.25 m focusing
+higher 0.15× magnification
+a 10-blade diaphragm

Where the Viltrox AF 33mm f/1.4 wins

+a brighter f/1.4 maximum aperture
+autofocus at all, where the Ultron 27mm F2 X is manual focus only

Who should buy the Ultron 27mm F2 X or Viltrox AF 33mm f/1.4?

Buy the Ultron 27mm F2 X if…

Pick the Ultron 27mm F2 X if a lighter 120g body and a more compact 23.5 mm barrel matter to you. Photographers who want the deliberate, set-the-camera-first way of shooting a rangefinder-style prime on a small Fuji body, and who value rendering and build over autofocus and sealing. Read the full Ultron 27mm F2 X review for the details.

Buy the Viltrox AF 33mm f/1.4 if…

Pick the Viltrox AF 33mm f/1.4 if a brighter f/1.4 maximum aperture and autofocus at all, where the Ultron 27mm F2 X is manual focus only matter to you. Anyone who wants a fast autofocusing normal prime without paying Fujifilm prices, and who shoots single-shot rather than tracking. Read the full Viltrox AF 33mm f/1.4 review for the details.

Ultron 27mm F2 X vs Viltrox AF 33mm f/1.4: pros and cons

Voigtländer Ultron 27mm F2 X	Viltrox Viltrox AF 33mm f/1.4
Sharp in the centre from f/2, with short focus falloff and clean specular highlights. All-metal build, third-stop aperture clicks, and a focus tab with a hard infinity stop. Ten straight blades give defined ten-point sunstars from around f/2.8. Electronic contacts: EXIF, focus peaking and check, distance display, IBIS, X-Pro3 parallax correction. 25 cm minimum focus at a 40 mm-equivalent view — close enough for detail work.	f/1.4 autofocus normal prime at roughly a third of the native price. Strong centre sharpness from f/1.4, even across the frame by f/2.8. Fast, effectively silent stepping-motor autofocus — quiet enough for video. User-updatable firmware over a USB port in the mount. HD Nano coating handles backlight without the milky wash cheap glass shows.
No autofocus, and a short focus throw that compresses everything past a few metres. Corners lag the XF 23mm F2 R WR wide open and only catch up around f/8. No weather sealing on a lens people mount to sealed X-Pro and X-T bodies. Post-2024 firmware on some Fuji bodies writes f/22 into EXIF instead of the set aperture. Around $600 — roughly 1.5× Fujifilm's own autofocusing 27mm pancake.	Clickless, unmarked aperture ring — smooth for video, imprecise for stills. No weather sealing and no stabilization. 270g and 72 mm long, noticeably bigger than the XF 35mm F1.4 R. Compatibility depends on firmware; the original needed a hardware revision for the X-Pro3. Viltrox's own store no longer lists the X-mount version, so future support is uncertain.

Voigtländer Ultron 27mm F2 X

Viltrox Viltrox AF 33mm f/1.4

Sharp in the centre from f/2, with short focus falloff and clean specular highlights.
All-metal build, third-stop aperture clicks, and a focus tab with a hard infinity stop.
Ten straight blades give defined ten-point sunstars from around f/2.8.
Electronic contacts: EXIF, focus peaking and check, distance display, IBIS, X-Pro3 parallax correction.
25 cm minimum focus at a 40 mm-equivalent view — close enough for detail work.

f/1.4 autofocus normal prime at roughly a third of the native price.
Strong centre sharpness from f/1.4, even across the frame by f/2.8.
Fast, effectively silent stepping-motor autofocus — quiet enough for video.
User-updatable firmware over a USB port in the mount.
HD Nano coating handles backlight without the milky wash cheap glass shows.

No autofocus, and a short focus throw that compresses everything past a few metres.
Corners lag the XF 23mm F2 R WR wide open and only catch up around f/8.
No weather sealing on a lens people mount to sealed X-Pro and X-T bodies.
Post-2024 firmware on some Fuji bodies writes f/22 into EXIF instead of the set aperture.
Around $600 — roughly 1.5× Fujifilm's own autofocusing 27mm pancake.

Clickless, unmarked aperture ring — smooth for video, imprecise for stills.
No weather sealing and no stabilization.
270g and 72 mm long, noticeably bigger than the XF 35mm F1.4 R.
Compatibility depends on firmware; the original needed a hardware revision for the X-Pro3.
Viltrox's own store no longer lists the X-mount version, so future support is uncertain.

Pros and cons mirror the in-house Ultron 27mm F2 X review and Viltrox AF 33mm f/1.4 review.

Ultron 27mm F2 X vs Viltrox AF 33mm f/1.4: full specs

Spec	Ultron 27mm F2 X 27 mm · f/2 · 120g	Viltrox AF 33mm f/1.4 33 mm · f/1.4 · 270g
Optical
Focal length	27 mm	33 mm
35mm equivalent	40 mm	50 mm
Maximum aperture	f/2	f/1.4
Minimum aperture	f/22	f/16
Optical construction	6 elements in 4 groups	10 elements in 9 groups
Special elements	1 extra-low-dispersion element, no aspherical glass	1 ED element, 1 high-refractive-index element, HD Nano coating
Aperture blades	10	9
Focus & Stabilization
Min. focus distance	0.25 m	0.40 m
Max. magnification	0.15×	0.1×
Autofocus motor	Manual focus only	Stepping motor
Optical stabilization	No	No
Physical
Filter thread	43 mm	52 mm
Diameter × length	59.3 × 23.5 mm	65 × 72 mm
Weight	120g	270g
Weather sealing	No	No
Min. operating temp	—	—
General
Announced	2023-05-15	2020-04-21

Highlighted cells are best in class between these two. Specs sourced from the manufacturers' public product pages.

In-depth reviews

For the full long-form review of each lens, see the Voigtländer Ultron 27mm F2 X review and the Viltrox Viltrox AF 33mm f/1.4 review. Each carries the full spec breakdown, pros and cons, and where the lens sits in the X-mount lineup.