We put the Crosscall Stellar-X5 through our rigorous SBMARK Display test suite to measure its performance Cons four criteria. In the results of this test, we will analyze how it performed in a series of tests and in several common use cases.
Overview
Key display specifications
- 6.5 inch IPS LCD
- Dimensions: 172.4 x 80.1 x 11.9 mm (6.79 x 3.15 x 0.47 inches)
- Resolution: 1080 x 2400 pixels, (density ~405 ppi)
- Aspect ratio: 20:9
- Refresh rate: 120Hz
Pros
- No dropped frames while watching videos
- Accurate on-screen interactions, with fast touch response
- No screen flickering
Against
- Poor readability in internal and external conditions
- Minimum luminance is too high in low light conditions
- Dark tones are not visible when watching HDR10 videos
- Brightness drops rapidly when viewing the screen from an angle
The Crosscall Stellar-X5’s screen delivered a very uneven performance in our display protocol, with the screen experience affected by a pinkish cast in all conditions.
While the Stellar-X5’s display luminance and contrast levels were able to match most ultra-premium phones in indoor conditions, the device’s display was still difficult to read, especially in bright outdoor environments. In complete darkness, the screen’s luminance remained too bright to provide a comfortable viewing experience.
Watching HDR10 video was also a mixed experience. While there were no frame drops, it was sometimes difficult to distinguish dark tones in video content due to the lack of brightness.
Otherwise, the Crosscall Stellar-X5’s liquid crystal display was virtually flicker-free, a phenomenon that’s more likely to occur in OLED displays, which are typically found on other ultra-premium phone displays.
While expected touch interactions on the display were often fast and accurate, the display often performed unwanted touches.
Test summary
About SBMARK display tests: For scoring and analysis, a device is subjected to a series of objective and perceptual tests under controlled laboratory and real-life conditions. The SBMARK Display Score takes into account the overall user experience provided by the screen, considering hardware capability and software optimization. Only factory-installed video and photo apps are used during testing. More in-depth details on how SBMARK tests displays can be found in the article “A Closer Look at SBMARK Display Testing.”
The following section focuses on the key elements of our comprehensive testing and analysis performed in SBMARK laboratories. Comprehensive reports with detailed performance evaluations are available upon request. To order a copy please contact us.
How the display readability score is composed
Readability evaluates the user’s ease and comfort in viewing stationary content, such as photos or a web page, on the display under different lighting conditions. Our measurements performed in laboratories are complemented by perceptual tests and analyses.
Skin tone rendering in an indoor environment (1000 lux).
From left to right: Crosscall Stellar-X5, Fairphone 4, Poco F4 GT, Samsung Galaxy A55 5G
(Photo for illustrative purposes only)
Skin tone rendering in a solar environment (>90,000 lux).
From left to right: Crosscall Stellar-X5, Fairphone 4, Poco F4 GT, Samsung Galaxy A55 5G
(Photo for illustrative purposes only)
SCI stands for Specular Component Included, which measures both diffuse reflection and specular reflection. The reflectance of a simple glass plate is around 4%, while it reaches around 6% for a plastic plate. Although the first surface of smartphones is glass, their total reflectance (uncoated) is usually around 5% due to multiple reflections created by the complex optical stack.
The average reflectance is calculated based on the spectral reflectance in the visible spectrum range (see graph below) and human spectral sensitivity.
Uniformity
This graph shows the luminance distribution across the entire display panel. Uniformity is measured with a 20% gray pattern, with bright green indicating ideal luminance. An evenly distributed bright green color across the screen indicates that the display brightness is uniform. Other colors indicate a loss of uniformity.
Displays flicker for 2 main reasons: refresh rate and pulse width modulation. Pulse width modulation is a modulation technique that generates pulses of variable width to represent the amplitude of an analog input signal. This measurement is important for comfort because low-frequency flickering can be perceived by some individuals and, in more extreme cases, can induce seizures. Some experiments show that discomfort can occur more frequently. A high PWM frequency (>1500 Hz) tends to disturb users less.
How the display color score is composed
Color evaluations are performed under different lighting conditions to see how well the device handles color with its surroundings. The devices are tested with sRGB and Display-P3 image models. Both faithful mode and default mode are used for our evaluation. Our measurements performed in laboratories are complemented by perceptual tests and analyses.
Circadian action factor is a metric that defines the impact of light on the human sleep cycle. It is the ratio between the light energy that contributes to sleep disturbances (centered around 450 nm, representing blue light) and the light energy that contributes to our perception (covering 400 nm to 700 nm and centered at 550 nm, which is green light). A high circadian action factor means that the ambient light contains strong blue light energy and is likely to affect the body’s sleep cycle, while a low circadian action factor means that the light has weak blue light energy and is less likely to affect sleep patterns.
How the Display Video score is composed
The video attribute evaluates the handling of Standard Dynamic Range (SDR) and High Dynamic Range (HDR10) video in indoor and low-light conditions. Our measurements performed in laboratories are complemented by perceptual tests and analyses.
Video rendering in a low light environment (0 lux).
Clockwise from top left: Crosscall Stellar-X5, Fairphone 4, Poco F4 GT, Samsung Galaxy A55 5G
(Photo for illustrative purposes only)
These indicators present the percentage of frame irregularity in a 30-second video. These irregularities are not necessarily perceived by users (unless they are all with the same timestamp) but are an indicator of performance.
How the Display Touch score is composed
We evaluate touch attributes in many types of content where touch is critical and requires different behaviors such as gaming (fast touch and response times), web (smooth page scrolling), and images (accurate and smooth navigation from image to image). other ).
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