LG K51S Smartphone Review – Too little, too late?
Comparison devices
Bewertung | Rating Version | Datum | Modell | Gewicht | Laufwerk | Groesse | Aufloesung | Preis ab |
|---|---|---|---|---|---|---|---|---|
| 75.9 % v7 (old) | v7 (old) | 09 / 2020 | LG K51S Helio P35 MT6765, PowerVR GE8320 | 195 g | 64 GB eMMC Flash | 6.55" | 1600x720 | |
| 75.5 % v7 (old) | v7 (old) | 12 / 2019 | LG K50S Helio P22 MT6762, PowerVR GE8320 | 194 g | 32 GB eMMC Flash | 6.50" | 1560x720 | |
| 79.7 % v7 (old) | v7 (old) | 09 / 2020 | Samsung Galaxy M21 Exynos 9611, Mali-G72 MP3 | 188 g | 64 GB UFS 2.1 Flash | 6.40" | 2340x1080 | |
| 77 % v7 (old) | v7 (old) | 08 / 2020 | Honor 9X Lite Kirin 710, Mali-G51 MP4 | 188 g | 128 GB eMMC Flash | 6.50" | 2340x1080 |
Case, equipment and operation - Eye-catching photo module
The LG K51S draws attention to itself with its back: The wide, but in the height very narrow camera module is definitely an eye-catcher. You can also customize the color selection thanks to the red or blue housing. For those who prefer a more reserved look, there is also a simple dark gray.
The workmanship looks good, material transitions are hardly noticeable and the stable smartphone housing also reacts to pressure with stoic composure.
The fact that NFC is on board is already a plus, making mobile payment services easy to use. Even the modern USB-C connection is not yet standard on all smartphones in this price class. 64 GB eMMC flash as mass storage and only 3 GB RAM, however, are somewhat stingy. In our tests with the reference router Netgear Nighthawk AX12, the WLAN also proved to be quite slow in a class comparison.
It's annoying that LG still relies on the older Android 9, for the predecessor LG K50S an update is only planned for the next months, if it stays at this speed, buyers of the LG K51S have to wait another year for an operating system update, then Android 10 would already be two years old again. Also the security patches are already clearly outdated at the time of testing.
The fingerprint sensor on the back can be easily felt and reacts quickly to a touch. The unlocking also works with only a short waiting time.
| Networking | |
| iperf3 transmit AX12 | |
| Samsung Galaxy M21 | |
| Honor 9X Lite | |
| LG K50S | |
| LG K51S | |
| iperf3 receive AX12 | |
| Samsung Galaxy M21 | |
| LG K50S | |
| Honor 9X Lite | |
| LG K51S | |
Cameras - One more lens in the K51S
Four camera modules are found in the K51S, compared to the predecessor K50S a macro lens has been added, but only with a very low 2 megapixel resolution. The wide angle lens still has 5 megapixels, the main camera now has a much higher resolution, namely 32 megapixels and recently also pixel binning, which is called Quad-Cell at LG. This means that four pixels are combined to one pixel on the finished image. This reduces the resolution to 8 megapixels, but increases the light sensitivity of the individual pixels. If desired, the full resolution can also be used.
Since macro lens is only used in the special macro mode, there is at least a multi-level zoom between wide angle and standard lens. The photos of the main camera look a bit pale in color, but are reasonably sharpened in detail, at least in the center of the picture. Sometimes, you can see clear pixel artifacts at the edges of the lens. With the wide angle lens, the sharpness in detail suffers, but the pictures are basically usable.
Videos can be recorded with a maximum of 1080p and 30 fps, you have to choose between a standard or a wide angle lens before recording. The brightness adjustment operates visibly graded, the compression of the videos also causes partly visible pixel artifacts during brightness transitions. The sharpness and brightness of the videos are, however, basically on a decent level.
The front camera with 13 megapixels has the same high resolution as its predecessor, it still makes acceptable selfies for the price range, but lacks sharpness of detail.
Image Comparison
Choose a scene and navigate within the first image. One click changes the position on touchscreens. One click on the zoomed-in image opens the original in a new window. The first image shows the scaled photograph of the test device.
Main Lens FlowerMain Lens EnvironmentMain Lens Low LightUltra wide angle
Display - LG phone with IPS display
Full-HD resolution in a smartphone for just under 200 euros manufacturer's price is actually no longer too much to ask. The LG K51S nevertheless relies on a lower resolution 720p IPS display. This puts it at a clear disadvantage compared to, for example, the Samsung Galaxy M21, which with its AMOLED display can not only be much brighter if necessary, but also offers better black levels and better color representation.
To be fair, however, it must also be said that the LG K51S display does not do its job so badly for an IPS display: the deviations in color representation are better than with the predecessor and the black level is acceptable. However, an average luminosity of 393 cd/m² is not enough even for an inexpensive mid-range smartphone in 2020.
A great advantage for sensitive people: There is no PWM flickering.
| |||||||||||||||||||||||||
Brightness Distribution: 95 %
Center on Battery: 407 cd/m²
Contrast: 768:1 (Black: 0.53 cd/m²)
ΔE Color 4.17 | 0.5-29.43 Ø4.91
ΔE Greyscale 3.8 | 0.5-98 Ø5.2
94.7% sRGB (Calman 2D)
Gamma: 2.235
| LG K51S IPS, 1600x720, 6.6" | LG K50S IPS, 1560x720, 6.5" | Samsung Galaxy M21 Super AMOLED, 2340x1080, 6.4" | Honor 9X Lite IPS, 2340x1080, 6.5" | |
|---|---|---|---|---|
| Response Times | -12% | 74% | 25% | |
| Response Time Grey 50% / Grey 80% * | 42 ? | 52 ? -24% | 10 ? 76% | 36 ? 14% |
| Response Time Black / White * | 28 ? | 28 ? -0% | 8 ? 71% | 18 ? 36% |
| PWM Frequency | 100 ? | 215.5 | ||
| Screen | -1% | 41% | -1% | |
| Brightness middle | 407 | 486 19% | 617 52% | 435 7% |
| Brightness | 393 | 464 18% | 614 56% | 422 7% |
| Brightness Distribution | 95 | 90 -5% | 95 0% | 93 -2% |
| Black Level * | 0.53 | 0.33 38% | 0.77 -45% | |
| Contrast | 768 | 1473 92% | 565 -26% | |
| Colorchecker dE 2000 * | 4.17 | 5.79 -39% | 2.11 49% | 3.31 21% |
| Colorchecker dE 2000 max. * | 8.28 | 11.87 -43% | 3.41 59% | 6.8 18% |
| Greyscale dE 2000 * | 3.8 | 7.1 -87% | 2.6 32% | 3.2 16% |
| Gamma | 2.235 98% | 2.283 96% | 2.073 106% | 2.3 96% |
| CCT | 7227 90% | 8511 76% | 6921 94% | 6894 94% |
| Total Average (Program / Settings) | -7% /
-3% | 58% /
49% | 12% /
5% |
* ... smaller is better
Display Response Times
| ↔ Response Time Black to White | ||
|---|---|---|
| 28 ms ... rise ↗ and fall ↘ combined | ↗ 15 ms rise |  |
| ↘ 13 ms fall | ||
| The screen shows relatively slow response rates in our tests and may be too slow for gamers. In comparison, all tested devices range from 0.1 (minimum) to 240 (maximum) ms. » 68 % of all devices are better. This means that the measured response time is worse than the average of all tested devices (20.9 ms). | ||
| ↔ Response Time 50% Grey to 80% Grey | ||
| 42 ms ... rise ↗ and fall ↘ combined | ↗ 23 ms rise |  |
| ↘ 19 ms fall | ||
| The screen shows slow response rates in our tests and will be unsatisfactory for gamers. In comparison, all tested devices range from 0.165 (minimum) to 636 (maximum) ms. » 64 % of all devices are better. This means that the measured response time is worse than the average of all tested devices (32.8 ms). | ||
Screen Flickering / PWM (Pulse-Width Modulation)
| Screen flickering / PWM not detected |  | ||
In comparison: 53 % of all tested devices do not use PWM to dim the display. If PWM was detected, an average of 8705 (minimum: 5 - maximum: 343500) Hz was measured. | |||
Performance, emissions and battery life - More power desirable
The LG K51S is equipped with a MediaTek Helio P35, which offers rather low performance compared to similarly expensive smartphones. Compared to its predecessor, it is after all a significant performance upgrade. For more complex apps, the smartphone is less suitable, but navigating through the menu is usually smooth.
The microSD reader does its job at a normal speed level, as we noticed in the test with the Toshiba Exceria Pro M501 reference card. In terms of internal memory, however, there are now significantly faster smartphones at this price level.
The warming under load is negligible and will hardly make itself unpleasantly noticeable even in hot environments.
The loudspeaker shows a rather similar sound image to its predecessor, i.e. strongly emphasized trebles, which make the sound seem less voluminous. However, voices are reproduced properly. The connection of external audio devices via 3.5mm connector or Bluetooth is no problem and delivers clean sound.
Unfortunately, our test device can't reach the runtimes of its predecessor in the WLAN test with fixed screen brightness. 13:23 hours is decent, but there are significantly more enduring smartphones at this price level. The charger has at least become a bit more powerful and now only needs about 2:30 hours for a full battery charge, but it's still far from a quick charge level.
| PCMark for Android | |
| Work performance score (sort by value) | |
| LG K51S | |
| LG K50S | |
| Samsung Galaxy M21 | |
| Honor 9X Lite | |
| Average Mediatek Helio P35 MT6765 (4040 - 7753, n=8) | |
| Work 2.0 performance score (sort by value) | |
| LG K51S | |
| LG K50S | |
| Samsung Galaxy M21 | |
| Honor 9X Lite | |
| Average Mediatek Helio P35 MT6765 (3814 - 5794, n=11) | |
| GFXBench | |
| on screen Aztec Ruins Normal Tier Onscreen (sort by value) | |
| LG K51S | |
| LG K50S | |
| Samsung Galaxy M21 | |
| Honor 9X Lite | |
| Average Mediatek Helio P35 MT6765 (3.5 - 7.6, n=12) | |
| Average of class Smartphone (3.6 - 247, n=204, last 2 years) | |
| 1920x1080 Aztec Ruins Normal Tier Offscreen (sort by value) | |
| LG K51S | |
| LG K50S | |
| Samsung Galaxy M21 | |
| Honor 9X Lite | |
| Average Mediatek Helio P35 MT6765 (3.8 - 4.2, n=12) | |
| Average of class Smartphone (2.3 - 263, n=204, last 2 years) | |
| on screen Aztec Ruins High Tier Onscreen (sort by value) | |
| LG K51S | |
| LG K50S | |
| Samsung Galaxy M21 | |
| Honor 9X Lite | |
| Average Mediatek Helio P35 MT6765 (2.2 - 4.8, n=11) | |
| Average of class Smartphone (0.85 - 144, n=204, last 2 years) | |
| 2560x1440 Aztec Ruins High Tier Offscreen (sort by value) | |
| LG K51S | |
| LG K50S | |
| Samsung Galaxy M21 | |
| Honor 9X Lite | |
| Average Mediatek Helio P35 MT6765 (1.4 - 1.5, n=11) | |
| Average of class Smartphone (0.85 - 112, n=204, last 2 years) | |
| LG K51S | LG K50S | Samsung Galaxy M21 | Honor 9X Lite | Average 64 GB eMMC Flash | Average of class Smartphone | |
|---|---|---|---|---|---|---|
| AndroBench 3-5 | -10% | 130% | 51% | 13% | 824% | |
| Sequential Read 256KB | 266.1 | 272.8 3% | 487.8 83% | 286.8 8% | 274 ? 3% | 1859 ? 599% |
| Sequential Write 256KB | 165.2 | 86.6 -48% | 192.7 17% | 200.9 22% | 176.2 ? 7% | 1445 ? 775% |
| Random Read 4KB | 58.9 | 54.3 -8% | 126 114% | 44.8 -24% | 59.4 ? 1% | 278 ? 372% |
| Random Write 4KB | 18.8 | 18.6 -1% | 124.2 561% | 72.4 285% | 32 ? 70% | 310 ? 1549% |
| Sequential Read 256KB SDCard | 79.6 ? | 78.3 ? -2% | 77.9 ? -2% | 76 ? -5% | 77.4 ? -3% | |
| Sequential Write 256KB SDCard | 59.3 ? | 58 ? -2% | 62.2 ? 5% | 69.2 ? 17% | 58.3 ? -2% |
Temperature
(+) The maximum temperature on the upper side is 38.3 °C / 101 F, compared to the average of 35.1 °C / 95 F, ranging from 21.9 to 63.7 °C for the class Smartphone.
(+) The bottom heats up to a maximum of 38.1 °C / 101 F, compared to the average of 33.9 °C / 93 F
(+) In idle usage, the average temperature for the upper side is 27.4 °C / 81 F, compared to the device average of 32.8 °C / 91 F.
Speakers
LG K51S audio analysis
(±) | speaker loudness is average but good (80.5 dB)
Bass 100 - 315 Hz
(-) | nearly no bass - on average 33.7% lower than median
(±) | linearity of bass is average (10.4% delta to prev. frequency)
Mids 400 - 2000 Hz
(+) | balanced mids - only 4.2% away from median
(±) | linearity of mids is average (8.4% delta to prev. frequency)
Highs 2 - 16 kHz
(+) | balanced highs - only 4.5% away from median
(+) | highs are linear (6.2% delta to prev. frequency)
Overall 100 - 16.000 Hz
(-) | overall sound is not linear (31.8% difference to median)
Compared to same class
» 80% of all tested devices in this class were better, 2% similar, 18% worse
» The best had a delta of 12%, average was 37%, worst was 134%
Compared to all devices tested
» 90% of all tested devices were better, 2% similar, 8% worse
» The best had a delta of 4%, average was 25%, worst was 134%
LG K50S audio analysis
(±) | speaker loudness is average but good (81.4 dB)
Bass 100 - 315 Hz
(-) | nearly no bass - on average 64% lower than median
(+) | bass is linear (0% delta to prev. frequency)
Mids 400 - 2000 Hz
(-) | nearly no mids - on average 64% lower than median
(+) | mids are linear (0% delta to prev. frequency)
Highs 2 - 16 kHz
(-) | nearly no highs - on average 64% lower than median
(+) | highs are linear (0% delta to prev. frequency)
Overall 100 - 16.000 Hz
(-) | overall sound is not linear (129.6% difference to median)
Compared to same class
» 98% of all tested devices in this class were better, 2% similar, 0% worse
» The best had a delta of 12%, average was 37%, worst was 134%
Compared to all devices tested
» 99% of all tested devices were better, 1% similar, 0% worse
» The best had a delta of 4%, average was 25%, worst was 134%
Battery life
| LG K51S 4000 mAh | LG K50S 4000 mAh | Samsung Galaxy M21 6000 mAh | Honor 9X Lite 3750 mAh | Average of class Smartphone | |
|---|---|---|---|---|---|
| Battery Runtime | |||||
| WiFi Websurfing | 803 | 946 18% | 1298 62% | 793 -1% | 985 ? 23% |
Pros
Cons
Verdict – Seems unfortunately antiquated
The LG K51S lags a generation behind similarly priced smartphones from 2020, not only in terms of software. Also in terms of performance, battery life, WLAN speed and screen brightness, people are now more used to getting more value for their money. The slow memory is another negative aspect.
But there are also positive things like the low temperature development, the stable case, which according to the manufacturer even underwent some stability tests according to MIL-STD-810G, or the at least solid sounding loudspeaker.
The LG K51S unfortunately falls behind the competition, but at least it can offer a flexible camera and a stable housing with an individually designed photo module.
In terms of flexibility and image quality, the camera is at least on a similar level to the competition, and with NFC there is the most important communication interface for mobile payment.
But the impression remains that there are simply better offers than the LG K51S. Although LG has praised the improvement in the frequency of software updates, there is unfortunately little evidence of this at present.
LG K51S
- 09/25/2020 v7 (old)
Florian Schmitt
Price comparison
