Xiaomi 13 Camera test

For scoring and analysis, SBMARK engineers capture and evaluate more than 2,600 test images in both controlled laboratory environments and outdoor, indoor, and low-light natural scenes using camera presets. The photographic protocol is designed to take into account the main use cases and is based on typical shooting scenarios, such as portrait, family and landscape photography. Evaluation is performed by visually inspecting images Cons a natural scene reference and by performing objective measurements on laboratory-acquired graph images under various lighting conditions from 1 to 1,000+ lux and color temperatures from 2,300 K to 6,500 K.

Exposure and color are key attributes for technically good images. For exposure, the main attribute evaluated is the brightness of the main subject across various use cases such as landscape, portrait or still life. Other factors evaluated are contrast and dynamic range, e.g. the ability to make details visible in light and dark areas of the image. Repeatability is also important because it demonstrates the camera’s ability to provide the same rendering when taking multiple images of the same scene.
For color, the image quality attributes analyzed are skin tone rendering, white balance, color shading, and repeatability. With regards to color rendition and skin tone, we penalize unnatural colors but respect the manufacturer’s choice of color signature.

Autofocus tests focus on focus accuracy, focus repeatability, shutter lag, and depth of field. Shutter lag is the difference between when the user presses the capture button and when the image is actually taken. It includes the speed of focusing and the ability of the device to capture images at the right moment, the so-called “zero shutter lag” capability. While a shallow depth of field can be nice for a single-subject portrait or close-up shot, it can also be a problem in some specific conditions like group portraits; Both situations are tested. Focus accuracy is also evaluated in all real-life images taken, from infinity to close-up objects and low-light to outdoor conditions.

Texture tests analyze the level of detail and texture of subjects in images taken in the lab as well as real-life scenarios. For natural shots, special attention is paid to the level of detail in the light and dark areas of the image. Objective measurements are performed on map images taken under various lighting conditions from 1 to 1000 lux and different types of dynamic range conditions. The charts used are the proprietary SBMARK (DMC) chart and the Dead Leaves chart.

Noise tests analyze various noise attributes such as intensity, chromaticity, grain, texture on real-life images and lab-captured graph images. For natural images, special attention is paid to noise on faces, landscapes, but also dark areas and high dynamic range conditions. Noise on moving objects is also evaluated on natural images. Objective measurements are performed on chart images captured under various conditions from 1 to 1000 lux and different types of dynamic range conditions. The graph used is the dead leaves graph and standardized measurement such as visual noise derived from ISO 15739.

Artifact assessment examines lens shading, chromatic aberrations, geometric distortion, ringing edges, halos, ghosting, quantization, unexpected color tone shifts, among other types of possible effects unnatural on photos. The more serious and frequent the artifact, the greater the deduction of points from the score. The main artifacts observed and the corresponding loss of points are listed below.

The preview tests analyze the image quality of the camera app’s image preview, with particular attention to the difference between the capture and the preview, especially regarding the dynamic range and the application of the bokeh effect. The uniformity of exposure, color and focus adaptation when zooming from the minimum to the maximum available zoom factor is also evaluated. The preview frame rate is measured using the Universal Timer LED.

SBMARK engineers capture and evaluate over 400 test images in controlled laboratory environments and natural outdoor, indoor, and low-light scenes using camera presets and pinch zoom at various zoom factors from ultra wide to very long zoom. Evaluation is performed by visually inspecting images Cons a natural scene reference and by performing objective measurements of lab-captured map images under varying conditions from 20 to 1000 lux and color temperatures from 2300K to 6500K.

These tests analyze the performance of the ultra wide angle camera at different focal lengths from 12mm to 20mm. All attributes of image quality are evaluated, with particular attention to artifacts such as chromatic aberrations, lens softness and distortion. The images below are an excerpt from the tested scenes.

All image quality attributes are evaluated at focal lengths from approximately 40mm to 300mm, with an emphasis on texture and detail. The score comes from a series of objective laboratory measurements and perceptual analysis of real-life images.

SBMARK engineers capture and evaluate more than 2.5 hours of video in controlled lab environments and low natural light scenes, indoors and out, using the camera’s default settings. Evaluation consists of visually inspecting natural video taken under various conditions and performing objective measurements on lab-recorded graph video under various conditions from 1 to 1000+ lux and color temperatures from 2,300K to 6,500K.

Exposure tests evaluate the brightness of the main subject and the dynamic range, e.g. the ability to make details visible in light and dark areas of the image. The stability and temporal adaptation of the exposure are also analysed.
Image quality color analysis examines color rendition, skin tone rendition, white balance, color shading, white balance stability and its adaptation when the light changes.

Texture tests analyze the level of detail and texture of real-life videos as well as graphics videos recorded in the lab. Natural video recordings are evaluated visually, with particular attention to the level of detail in bright areas and dark areas. Objective measurements of card images taken under various conditions from 1 to 1000 lux are performed. The charts used are the SBMARK (DMC) chart and the Dead Leaves chart.

Noise tests analyze various noise attributes such as intensity, chromaticity, grain, texture, temporal aspects on real-life video recording, as well as graph videos taken in the lab. Natural videos are evaluated visually, with an emphasis on noise in dark areas and high dynamic range conditions. Objective measurements are performed on graph videos recorded under various conditions from 1 to 1000 lux. The graph used is the SBMARK visual noise graph.

The stabilization rating tests the device’s ability to stabilize footage using software or hardware technologies such as OIS, EIS, or any other means. The evaluation looks at residual motion, smoothness, yellow artifacts, and residual motion blur in walking and running use cases under various lighting conditions. The video below is an excerpt from one of the tested scenes.

Artifacts are evaluated with MTF and ringing measurements on the SFR graph in the lab, as well as frame rate measurements using the Universal Timer LED. Natural videos are visually evaluated by paying close attention to artifacts such as aliasing, quantization, blocking, and pitch shifting, among others. The more severe and frequent the artifact, the more points will be deducted from the score. The main artifacts and the corresponding point loss are listed below.