DxOMark Mobile Report: BlackBerry Priv
The BlackBerry Priv combines Google's Android operating system with BlackBerry's security features and a slider form factor with hardware qwerty-keyboard. In the camera module an 18MP sensor works together with a Schneider Kreuznach designed lens and optical image stabilization. The camera is capable of recording 4K video and there is also a dual-tone LED flash. 32GB of built-in storage can be expanded via a microSD-slot.
With a DxOMark Mobile score of 82, the BlackBerry Priv performs on the same level as Apple's iPhone 6s or the Sony Xperia Z3+ and occupies a joint eleventh place in the DxOMark smartphone rankings. The DxOMark testers liked the 'very good exposure with wide dynamic range, generally accurate and fast autofocus, well-preserved detail, especially in bright light, pleasant colors and good overall flash performance'. Points of criticism included the 'sometimes inaccurate white balance, strong ringing, comparatively high noise levels in bright light and over-saturated colors when shooting with flash'.
In video mode the DxO team liked the 'very good noise reduction, good detail preservation in bright light and the accurate and smooth autofocus'. On the downside, 'stabilization causes visible frame shifts and rotations, a pink cast is visible in low light and the lens sometimes refocuses unnecessarily'.
Color, Exposure and Contrast
The DxOMark team found that the BlackBerry Priv images showed 'very good exposure with wide dynamic range and pleasant colors'. As negatives they noted that the 'white balance is sometimes inaccurate, with a yellow, pink or blue cast in bright light'. They also noted 'some color shading in outdoor and low light conditions' and a 'pinkish cast in low tungsten light'.
Overall DxOMark awarded the BlackBerry Priv scores of:
- 4.7 out of 5 for Exposure
- 4.1 out of 5 for White Balance accuracy
- 3.3 out of 5 for Color shading in low light*
- 4.1 out of 5 for Color shading in bright light*
- 3.0 out of 5 for Color Rendering in low light
- 4.5 out of 5 for Color Rendering in bright light
*Color Shading is the nasty habit cellphone cameras have of rendering different areas of the frame with different color shifts, resulting in pictures with, for example, pinkish centers and greenish corners.
Noise and Details
DxOMark's engineers reported that the BlackBerry Priv images show 'well preserved detail, especially in bright light' but 'compared to other smartphones noise levels are high in bright light'.
Texture acutance is a way of measuring the ability of a camera to capture images that preserve fine details, particularly the kind of low contrast detail (such as fine foliage, hair or fur) that can be blurred away by noise reduction or obliterated by excessive sharpening.
Sharpness is an important part of the quality of an image, but while it's easy to look at an image and decide visually whether it's sharp or not, the objective measurement of sharpness is less straightforward.
An image can be defined as 'sharp' if edges are sharp and if fine details are visible. In-camera processing means that it's possible to have one of these (sharp edges) but not the other (fine details). Conventional MTF measurements tell us how sharp an edge is, but have drawbacks when it comes to measuring fine detail preservation. Image processing algorithms can detect edges and enhance their sharpness, but they can also find homogeneous areas and smooth them out to reduce noise.
Texture acutance, on the other hand, can qualify sharpness in terms of preservation of fine details, without being fooled by edge enhancement algorithms.
At first sight, the images from these two cameras may appear equally sharp. A sharpness measurement on edges will indeed confirm this impression, and will even show that the second camera is sharper. But a closer examination of low contrasted textures shows that the first camera has better preservation of fine details than the second. The purpose of the texture acutance measurement is to qualify this difference.
Visual noise is a value designed to assess the noise in an image as perceived by the human visual system, depending on the viewing condition (size of image, size of screen or print, viewing distance). The measurements have no units and can be simply viewed as the weighted average of noise standard deviation for each channel in the CIE L*a*b* color space. The lower the measurement, the less noise in the image.
Noise and Detail Perceptual scoring
- Texture (bright light): 4.8 out of 5
- Texture (low light): 3.7 out of 5
- Noise (bright light): 3.8 out of 5
- Noise (low light) 3.2 out of 5
Phone cameras, like entry-level compact cameras, tend to suffer from artifacts such as sharpening halos, color fringing, vignetting (shading) and distortion, which can have an impact on the visual appeal of the end result. DxOMark engineers measure and analyze a range of artifacts. Their findings after testing the BlackBerry Priv are shown below:
- Strong ringing is visible
- Slight tone curve compression due to aggressive HDR mode
- Sharpness 4.2 out of 5
- Color fringing 4.0 out of 5
- Ringing center 26.1%
- Ringing corner 20.0%
- Max geometric distortion -0.3%
- Luminance shading 16.8%
Distortion and Chromatic Aberrations
DxOMark also tests autofocus accuracy and reliability by measuring how much the acutance - or sharpness - varies with each shot over a series of 30 exposures (defocusing then using the autofocus for each one). As with other tests these results are dependent on the viewing conditions (a little bit out of focus matters a lot less with a small web image than a full 8MP shot viewed at 100%). Using the 8MP equivalent setting, the BlackBerry Priv performs well in all light conditions. The overall score is 81/100 in bright light and 86/100 in low light.
- Generally accurate and fast autofocus in all conditions
- Irregularities and occasional failure in trigger mode
- Slight overshoot visible in low light preview mode
The BlackBerry Priv offers a dual-tone LED flash for better color balance. DxOMark scored the camera 83/100 overall for its flash performance.
- Accurate white balance when flash is mixed with additional light sources
- Good color rendering in mixed light
- Low noise levels and good detail preservation
- White balance slightly biased towards red/yellow when shooting without ambient light sources
- Slightly oversaturated colors when shooting without ambient light sources
Overall DxOMark Mobile Score for Photo: 82 / 100
DxOMark engineers put phone cameras through a similarly grueling set of video tests, and you can read their full findings on the DxOMark website here. Overall, DxOMark found the BlackBerry Priv video footage to show good detail and low noise levels. However, the stabilization system can cause artifacts and low light footage shows a pink color cast.
- Very good noise reduction
- Good detail preservation, particularly in bright light
- Accurate and smooth autofocus
- Stabilization causes visible frame shifts and rotations
- Visible pink cast in low light
- Lens sometimes refocuses unnecessarily
Overall DxOMark Mobile Score for Video: 81 / 100
DXOMark Image Quality Assessment
In testing the Priv images were well exposed, with good dynamic range. Image detail is very good in bright light but drops a little in dimmer conditions. The testers also liked the fast and precise autofocus but criticized occasional white balance inaccuracies and higher than usual noise levels in good light.
Video footage shows good detail in bright light but suffers from frame shifts and rotation caused by the stabilization system. For a more detailed analysis, visit www.dxomark.com.
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