DxOMark Mobile Report: Blackberry Z10

DxOMark Mobile Report: Blackberry Z10

Blackberry, once the undisputed market leader in the smartphone world, has continuously been losing market share since the launch of the iPhone in 2007 and many were probably expecting the brand to totally disappear in a not too distant future.

However, with its new Blackberry 10 operating system the Canadian manufacturer is making an attempt to become relevant again in the mobile space.  Blackberry debuted the OS with two new devices. While the Q10, with its physical keyboard, follows in the footsteps of earlier Blackberry models, the Z10, which we cover here, features a touchscreen, placing it in direct competition to Apple’s iPhone and high-end Android models from Samsung, LG, HTC and the like.

The DxOMark Mobile Report includes DxO Lab’s usual industrial-quality scientific measurements. Its imaging experts have analyzed 14 aspects of mobile imaging including detailed image quality assessment, flash performance, autofocus reliability and more to calculate a final score. This report will be integrated into ur full review once it is finsihed but for now scroll down to find out how the Blackberry Z10’s camera performed in the DxO lab tests.

Blackberry Z10 headline features:

  • 8-megapixel camera, backside-illuminated CMOS sensor
  • F2.2 lens, 5 elements
  • 2MP front-facing camera
  • 4.2-inch touchscreen (1280 x 786 pixels, 356ppi)
  • 1.5GHz dual-core CPU
  • 2GB RAM
  • 16GB of internal storage
  • MicroSD card slot
  • NFC

Summary

With a DxOMark Mobile score of 67 the Blackberry Z10 is ranked toward the lower end  of the DxO smartphone ranking. Its score is one point above the HTC 8X and Nokia Lumia 920 Windows phones, but it cannot keep up with the best in class such as the Nokia 808, Apple iPhone 5 or Samsung Galaxy S3. 

The DxOMark team report that the Blackberry Z10 captures images with “Nice detail preservation including in low light conditions,” “good white balance,” overall good auto exposure” and “accurate autofocus in most situations.” 

On the downside: Images show “very strong luminance noise in low light,” “clearly visible color shading with tungsten light source in low light or D50 lighting” and “slight color fringing. When using the flash, white balance can be inaccurate.” Color shading occurs when flash is mixed with a tungsten light source.

In video mode, DxOMark’s engineers reported that the Blackberry Z10 offers “reactive autofocus with some tracking abilities,” but on the downside video footage shows “visible color non-uniformities,” “perfectible texture reproduction” and provides “inefficient video stabilization.”

Still Photography

Color, Exposure and Contrast

The DxOMark team found that the Blackberry Z10’s images show “overall good auto exposure,” “nice and pleasant colors outdoors” and “good white balance.” However, the Blackberry tends to underexpose in low light and shows “slight color shading with tungsten light source in low light or D50 lightings.” Because of this DxOMark scored the Blackberry Z10 at 81/100 for color in bright light and 65/100 in low light.   

Overall DxOMark awarded the Blackberry Z10 scores of:

  • 4.2 out of 5 for Exposure
  • 4.0 out of 5 for White Balance accuracy
  • 3.0 out of 5 for Color shading in low light*
  • 3.5 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 Z10 image output shows “nice detail preservation including in low light conditions.” On the other hand luminance noise is “very strong in low light conditions.”

Texture Acutance

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 (textures such as fine foliage, hair, 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 is 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 its edges are sharp and if fine details are visible, but in-camera processing means 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.

A detail of  target made of a dead leaves pattern, designed to measure Texture Acutance. It is obtained by drawing random shapes that occlude each other in the plane, like dead leaves falling from a tree. The statistics of this model follow the distribution of the same statistics in natural images.

In this example from a DSLR without edge enhancement, sharpness seems equal on edge and on texture. Many details are visible in the texture.

In this second example edges have been digitally enhanced, and the edge looks over-sharp, with visible processing halos (“ringing”). On the texture part, many details have disappeared.

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 a better preservation of fine details than the second. The purpose of the Texture Acutance measurement is to qualify this difference.

Edge Acutance

Visual Noise

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 a 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

Natural scene

  • Texture (bright light): 4.5 out of 5
  • Texture (low light): 3.0 out of 5
  • Noise (bright light): 3.5 out of 5
  • Noise (low light) 2.0 out of 5

Artifacts

Phone cameras, like entry-level compact cameras, tend to suffer from artifacts such as sharpening halos, color fringing, vignetting (shading) and distortion, which can impact on the visual appeal of the end result. DxOMark engineers measure and analyse a range of artifacts. Their findings after testing the Blackberry Z10 are shown below:

Pros:

  • n/a

Cons 

  • Slight loss of sharpness in image corners
  • Strong color fringing
  • Slight ringing

Perceptual scores

  • Sharpness 4.0 out of 5
  • Color fringing 4.0 out of 5

Measured findings

  • Ringing center: 14.1%
  • Ringing corner 6.1%
  • Max geometric distortion -0.29%
  • Luminance shading 26%

Distortion and Chromatic Aberrations

Autofocus

DxOMark also tests autofocus accuracy and reliability by measuring how much the accutance — 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 dependant 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 condition the Blackberry Z10 results are decent but not quite up there with the very best. The overall score is 75/100 in bright light and 64/100 in low light.

Pros: 

  • Autofocus is accurate and repeatable in bright light conditions
  • Good sharpness levels even in low light

Cons: 

  • Autofocus is slow

Flash


Source Article from http://connect.dpreview.com/post/4664104595/dxomark-mobile-report-blackberry-z10

Share on FacebookTweet about this on TwitterShare on Google+Pin on PinterestShare on TumblrShare on RedditShare on StumbleUponShare on LinkedInEmail this to someone