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Reviewed on Jul 16, 2019

LG UltraFine 4k
MONITOR REVIEW

Usage Ratings - Version 1.0
7.4
Mixed Usage
7.8
Office
7.4
Gaming
7.3
Multimedia
7.3
Media Creation
5.6
HDR Gaming
Size : 24 "
Resolution : 3840x2160
Refresh Rate : 60 Hz
LCD Type
:
IPS
Variable Refresh Rate
:
No

The LG UltraFine 4k is a decent 23.7 inch, 4k monitor. It delivers decent overall picture quality, with very good low input lag and decent motion handling. Like most IPS monitors, it has great wide viewing angles. This monitor has outstanding peak brightness and excellent gray uniformity, but it has mediocre reflection handling and doesn't look as good in a really bright room. Unfortunately, the backlight has a strange flicker frequency, which results in noticeable duplications in motion. It also doesn't look as good in a dark room, which is typical of IPS monitors.

This monitor is marketed towards Mac computers and only has USB-C inputs, which might be an issue for some PC users. This monitor doesn't have any controls, either, and no on-screen display, which is a bit strange.

Test Results
Design 7.5
Picture Quality 7.0
Motion 7.0
Inputs 8.6
Pros
  • Great peak brightness.
  • Image remains accurate when viewed at an angle.
Cons
  • Strange backlight flicker, which causes noticeable duplications.
  • No HDMI or DisplayPort connections.

Check Price

23.7" UltraFine 4k
Unavailable
Amazon.com
7.5

Design

Curved : No
Curve radius : N/A
Weight (without stand)
:
11.5 lbs (5.2 kg)
Weight (with stand)
:
15.4 lbs (7.0 kg)

The LG UltraFine 4k has a good, simple, yet relatively bulky design, similar to the Samsung Space SR75. The stand has a good height adjustment and tilt range, but lacks a swivel feature and can't be rotated to portrait orientation. The stand is good quality and supports the monitor well, with very little wobble.

Stand
Width
:
7.7" (19.6 cm)
Depth
:
9.1" (23.1 cm)

The stand is very basic, but solid, and supports the monitor very well, with almost no wobble.

4.8 Ergonomics
Height Adjustment
:
4.3" (10.9 cm)
Switch portrait/landscape : No
Swivel Range : N/A
Tilt Range : -25° to 5°

Unfortunately, the stand has bad ergonomics. It has a decent height adjustment and excellent tilt range, but it can't swivel, and can't rotate to portrait orientation.

Back
Wall Mount : VESA 100x100

The back is very simple. The inputs are all grouped together, but aren't very accessible if the monitor is wall-mounted. There is absolutely no cable management.

There is a quick release for the stand, and there is an included panel that hides the monitor's internals.

Borders
Borders
:
0.7" (1.8 cm)

The borders are thicker than most recent monitors, but they look good and aren't very distracting.

Thickness
Thickness (with stand)
:
5.7" (14.5 cm)
Thickness (without stand)
:
2.0" (5.1 cm)

This monitor is a bit thicker than most monitors, mainly due to the thickness of the stand. When VESA mounted, it's quite a bit thinner and looks good.

7.5 Build Quality

Good build quality overall, with no obvious concerns. Most of the external shell is made of plastic, but the stand is metal and supports the monitor well.

7.0

Picture Quality

The LG UltraFine 4k 23.7 delivers decent overall picture quality. Like most IPS monitors, it can't display deep blacks, which is especially noticeable in a dark room, and it doesn't have a local dimming feature. On the other hand, it has excellent peak brightness, very good viewing angles, and excellent gray uniformity. This monitor also has an outstanding color gamut and can display almost all of the DCI-P3 color space, even though it doesn't support HDR. Unfortunately, there is noticeable image retention (temporary), and the glossy finish isn't ideal if you have a lot of direct lighting.

6.6 Contrast
Native Contrast
:
1445 : 1
Contrast with local dimming
:
N/A

The LG UltraFine 4k has a decent contrast ratio and is one of the better IPS monitors we've tested. Although it still can't display true blacks in a dark room, there are no issues in a bright or medium-lit room.

0 Local Dimming
Local Dimming
:
No
Backlight
:
Edge

The LG UltraFine 4k does not support local dimming. The above video is for reference only.

8.6 SDR Peak Brightness
SDR Real Scene
:
554 cd/m²
SDR Peak 2% Window
:
563 cd/m²
SDR Peak 10% Window
:
563 cd/m²
SDR Peak 25% Window
:
563 cd/m²
SDR Peak 50% Window
:
563 cd/m²
SDR Peak 100% Window
:
562 cd/m²
SDR Sustained 2% Window
:
562 cd/m²
SDR Sustained 10% Window
:
562 cd/m²
SDR Sustained 25% Window
:
562 cd/m²
SDR Sustained 50% Window
:
561 cd/m²
SDR Sustained 100% Window
:
561 cd/m²
SDR ABL
:
0.000

Excellent peak brightness on this monitor. There is very little variation in brightness with different content. These results are very close to LG's posted specs.

0 HDR Peak Brightness
HDR Real Scene
:
N/A
HDR Peak 2% Window
:
N/A
HDR Peak 10% Window
:
N/A
HDR Peak 25% Window
:
N/A
HDR Peak 50% Window
:
N/A
HDR Peak 100% Window
:
N/A
HDR Sustained 2% Window
:
N/A
HDR Sustained 10% Window
:
N/A
HDR Sustained 25% Window
:
N/A
HDR Sustained 50% Window
:
N/A
HDR Sustained 100% Window
:
N/A
HDR ABL
:
N/A

This monitor does not support HDR.

7.3 Horizontal Viewing Angle
Color Shift from Left
:
37 °
Color Shift from Right
:
40 °
Brightness from Left
:
45 °
Brightness from Right
:
48 °
Black Level from Left
:
75 °
Black Level from Right
:
75 °
Curve Radius : N/A

This monitor has decent horizontal viewing angles. Black levels remain constant, even at wide angles, but the brightness fades gradually off-of-center, and colors shift and gradually lose accuracy. The angles are wide enough though that most people shouldn't have any issues.

8.3 Vertical Viewing Angle
Color Shift from Below
:
29 °
Color Shift from Above
:
29 °
Brightness from Below
:
37 °
Brightness from Above
:
37 °
Black Level from Below
:
75 °
Black Level from Above
:
75 °

The vertical viewing angles are great, and there shouldn't be any issues sharing your screen with someone standing beside you. Colors shift a bit quicker than on the horizontal axis, but otherwise, there are no serious issues.

8.7 Gray Uniformity
50% Std. Dev.
:
2.882 %
50% DSE
:
0.109 %
5% Std. Dev.
:
0.396 %
5% DSE
:
0.053 %

Excellent gray uniformity. There is only minor vignetting, and almost no noticeable dirty-screen effect, which is great. In near-dark scenes, the uniformity is significantly better.

6.3 Black Uniformity
Native Std. Dev.
:
1.805 %
Std. Dev. w/ L.D.
:
N/A

Mediocre black uniformity. There is some noticeable backlight bleed on the right-hand side; this can vary between units, though.

7.7 Pre Calibration
Picture Mode
:
N/A
Luminance
:
292 cd/m²
Luminance Settings
:
50
Contrast Setting
:
N/A
RGB controls
:
N/A
Color Temperature
:
6427 K
White Balance dE
:
2.02
Color dE
:
3.54
Gamma
:
2.24

Out of the box, the LG UltraFine 4k has good accuracy. The white balance is excellent, and there are no noticeable issues. Color accuracy is decent, but the primaries are noticeably over-saturated, as the monitor is targeting DCI-P3 out of the box. Gamma doesn't follow the sRGB target curve at all. Note that this monitor has no settings on the monitor itself.

9.7 Post Calibration
Picture Mode
:
N/A
Luminance
:
103 cd/m²
Luminance Settings
:
18
Contrast Setting
:
N/A
RGB Controls
:
N/A
Color Temperature
:
6455 K
White Balance dE
:
0.51
Color dE
:
0.29
Gamma
:
2.18

After calibration, the UltraFine 4k 23.7 has outstanding accuracy. Any remaining inaccuracies in colors and the white balance are unnoticeable, and gamma follows the target sRGB curve almost perfectly.

You can download our ICC profile calibration here. This is provided for reference only and should not be used, as the calibration values vary per individual unit even for the same model due to manufacturing tolerances.

9.2 SDR Color Gamut
sRGB xy
:
99.6 %
Adobe RGB xy
:
84.9 %

sRGB Picture Mode: Max backlight, (calibrated)
Adobe RGB Picture Mode: Max backlight

Excellent SDR color gamut, with perfect coverage of the sRGB color space, and great coverage of the wider Adobe RGB color space.

9.4 SDR Color Volume
sRGB in ICtCp
:
97.8 %
Adobe RGB in ICtCp
:
89.5 %

sRGB Picture Mode: Max backlight
Adobe RGB Picture Mode: Max backlight

Excellent SDR color volume. Due to the low contrast ratio, this monitor can't display dark, saturated colors very well.

0 HDR Color Gamut
Wide Color Gamut
:
N/A
DCI P3 xy
:
N/A
Rec. 2020 xy
:
N/A

This monitor does not support HDR, but it targets the DCI-P3 color space out of the box. It can display 95.9% of the DCI-P3 color space, which is excellent.

0 HDR Color Volume
DCI-P3 in ICtCp
:
N/A
Rec. 2020 in ICtCp
:
N/A

This monitor does not support HDR.

5.6 Image Retention
IR after 0 min recovery
:
0.37 %
IR after 2 min recovery
:
0.10 %
IR after 4 min recovery
:
0.00 %
IR after 6 min recovery
:
0.00 %
IR after 8 min recovery
:
0.00 %
IR after 10 min recovery
:
0.00 %

Unfortunately, there are some signs of temporary image retention, and it takes a few minutes for the retained image to dissipate. This is after displaying our high-contrast, static test image for 10 minutes. With varied enough content, this shouldn't be an issue for most people.

9.9 Gradient
Color Depth
:
10 Bit

Outstanding gradient handling on the UltraFine 4k. There is almost no banding noticeable in any shade.

10 Color Bleed
Pixel row error
:
0.004 %
Pixel column error
:
0.004 %

The UltraFine 4k has no noticeable color bleed, which is great.

6.0 Reflections

Unfortunately, the glossy finish is mediocre for reflection handling, as any nearby light sources are reflected directly off the screen, and aren't diffused across it.

7.0

Motion

Decent motion handling on the LG UltraFine 4k. It has a great response time, with very little overshoot, but unfortunately, the backlight has a very strange flicker behavior, and there are noticeable duplications in motion. This monitor has a simple 60Hz refresh rate and doesn't support any variable refresh rate technologies, like FreeSync or G-SYNC.

8.5 Motion Blur
80% Response Time
:
5.6 ms
100% Response Time
:
13.9 ms
Best Overdrive Setting
:
N/A

This monitor has a great response time, about average for 60Hz monitors. Most transitions are about the same speed, and there is no noticeable over/undershoot, which is great. Unlike the vast majority of monitors, the overdrive can't be changed.

Unfortunately, there are noticeable duplications in motion due to the backlight flicker.

5.7 Image Flicker
Flicker-free : No
PWM Dimming Frequency
:
700 Hz
Black Frame Insertion (BFI)
:
No
BFI Maximum Frequency
:
N/A
BFI Minimum Frequency
:
N/A

Unfortunately, at any setting other than maximum or minimum, there is flicker in this monitor's backlight. There appear to be multiple flicker frequencies interfering with one another, resulting in the strange interference pattern shown here. The overall flicker frequency appears to be about 700Hz, which isn't very noticeable, but duplications can be seen in some content.

6.7 Refresh Rate
Native
:
60 Hz
Factory Overclock
:
N/A
Variable Refresh Rate
:
No
G-SYNC Compatible
:
No
VRR Maximum
:
N/A
VRR Minimum
:
N/A
VRR Maximum With OC
:
N/A
VRR Supported Connectors : N/A

This monitor has a basic 60Hz refresh rate and doesn't support any variable refresh rate technologies, like FreeSync or G-SYNC.

8.6

Inputs

The LG UltraFine 4k 23.7 has great low input lag, although it's higher than most monitors currently on the market. The 24" display is a bit small, but the 4k resolution delivers an extremely sharp image.

8.4 Input Lag
Native Resolution
:
13.2 ms
Non-Native Res @ Native Refresh
:
11.3 ms
Native Resolution @ 60 Hz
:
13.2 ms
Variable Refresh Rate
:
N/A
10 bit HDR
:
N/A
Black Frame Insertion (BFI)
:
N/A

The LG UltraFine 4k has very good low input lag, but it's a bit higher than most 60Hz monitors. The non-native input lag is lower than the native resolution input lag, which is unexpected, but we don't know why this is.

8.9 Resolution and Size
Native Resolution : 3840 x 2160
Aspect Ratio : 16:9
Megapixels : 8.3 MP
Pixel Density : 186 PPI
Screen Diagonal : 23.7 inches
Screen Area : 240 sq inches

The 4k resolution is great and offers the highest pixel density of any monitor we've tested so far.

Some people have reported issues with scaling on this monitor, as the pixel density is lower than the 220 PPI (pixels-per-inch) target for retina displays. In normal usage, we didn't see any issues with this monitor, but for some users, it might be best to run this monitor at its native resolution, which does result in some UI elements appearing very small.

Inputs
Total Inputs
DisplayPort : No
Mini DisplayPort : No
HDMI : No
DVI : No
VGA : No
DisplayPort Out : No
USB : No
USB C : 5 (2x Thunderbolt 3 with PD, 3x USB-C)
Analog Audio Out 3.5mm : No
Microphone In 3.5mm : No
Digital Optical Audio Out : No
Analog Audio Out RCA : No

The LG UltraFine 4k has 3 USB-C ports and two Thunderbolt 3 ports, but no HDMI or DisplayPort connections. The two Thunderbolt ports support power delivery up to 85W, which is enough to charge even a 15" MacBook Pro at full speed. One of the Thunderbolt 3 ports can also be used to daisy-chain a second monitor.

Features

This is a basic monitor, with almost no additional features. It doesn't support HDR10 but does have integrated speakers. Strangely, this monitor has no on-screen display and no physical controls whatsoever, not even a power button.

Additional Features
Speakers
:
Yes
HDR10 : No
Multiple input display
:
No

This monitor has very few additional features. It has built-in speakers and an impressive USB-C hub, which includes 2 Thunderbolt 3 ports which can be used to charge almost any MacBook at full speed.

On-Screen Display (OSD)

There is no on-screen display on this monitor.

Controls

The LG UltraFine 4k 23.7 has no physical controls, not even a power button. It's designed to interface directly with a Mac and automatically turns on when the Mac is on. Brightness and volume are controlled directly on the Mac.

In The Box

  • USB-C cable
  • Thunderbolt 3 cable
  • VESA design cover
  • Manual
  • Power cable

Differences between Sizes and Variants

We tested the 23.7" LG UltraFine 4k, which is the only size currently available.

If someone comes across a different type of panel or if their LG UltraFine 4k doesn't correspond to our review, let us know and we will update the review. Note that some tests such as the gray uniformity may vary between individual units.

Model Size Resolution Refresh Rate Notes
UltraFine 4k 23.7" 4k 60Hz  

Compared to other Monitors

Left: LG 27UD58-B. Middle: LG UltraFine 4k. Right: BenQ EW3270.
Unlike our other photographs, this picture wasn't taken under a controlled environment, so do not draw conclusions from it.

The LG UltraFine 4k is a decent monitor for most uses, but there are much better monitors for less. See our recommendations for the best monitors, the best 4k monitors, and the best monitors for MacBook Pro.

LG 27UK650-W

The LG 27UK650-W is much better than the LG UltraFine 4k. The 27UK650 has better ergonomics, better reflection handling, a flicker-free backlight, and it supports HDR. The 27UK650 also has better gaming performance, with less input lag and support for FreeSync variable refresh rate technology.

Samsung Space SR75

The LG UltraFine 4k is better than the Samsung Space SR75 for most uses. The LG has a higher resolution screen, much better viewing angles, and better black uniformity. The Space has better ergonomics, better reflection handling, and a flicker-free backlight.

BenQ EL2870U

The LG UltraFine 4k is a bit better than the BenQ EL2870U for most uses. The LG has better viewing angles, better uniformity, and slightly better ergonomics. The BenQ EL2870U, on the other hand, supports HDR, has better reflection handling, and has a flicker-free backlight.

LG 27UD68

The LG 27UD68 is a bit better than the LG UltraFine 4k for most users. The 27UD68 has better ergonomics, better reflection handling, and a flicker-free backlight. The 27UD68 also delivers better gaming performance, with less input lag and FreeSync variable refresh rate support.

Conclusion
Unavailable
Amazon.com

7.4 Mixed Usage
The LG UltraFine 4k 23.7 is a decent monitor for most uses. It's best suited for office use, with wide viewing angles, a high-resolution screen, and excellent uniformity. It isn't as well-suited for gaming, due to the simple 60Hz refresh rate and lack of advanced gaming features.
7.8 Office
This is a very good monitor for office use. The 24", 4k screen delivers great screen real-estate and has wide viewing angles and excellent gray uniformity. The stand has bad ergonomics, though; it can't swivel, and can't rotate to portrait orientation.
7.4 Gaming
Decent monitor for gaming. It has a fast response time, but the strange backlight flicker causes noticeable duplications. Unfortunately, it has a simple 60Hz refresh rate and doesn't support any advanced gaming features, like FreeSync.
7.3 Multimedia
This is a decent choice for multimedia. The 4k resolution is great for watching the latest 4k movies, and it has wide viewing angles and great peak brightness. Unfortunately, it doesn't look quite as good in a dark room, and the strange backlight flicker causes noticeable duplications in motion.
7.3 Media Creation
This is a decent monitor for media creation. The 24", 4k screen is great and allows you to see more of your work at once. It also has very good viewing angles, low input lag, and a fast response time. Unfortunately, the stand has bad ergonomics, so it might be difficult to place in an ideal viewing position.
5.6 HDR Gaming
This monitor doesn't support HDR. For a good 4k gaming monitor with HDR, check out the LG 27UK650.

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