8: DxOMark Mobile ReportNext
HTC One M8 Camera Review
Lars Rehm | Published: May 27, 2014 at 18:14 UTC53
DxOMark Mobile Report: HTC One M8
With a DxOMark Mobile score of 68 the HTC One M8 cannot quite keep up with other current flagship phones and slots in at number 15 in the DxOMark smartphone rankings, placing itself between the Samsung Galaxy Note II and Blackberry Z10.
The DxOMark team reports the HTC One M8 delivers "nice and pleasant colors outdoors", "good details for outdoor images" and a "fast and precise autofocus in most situations".
On the downside, DxO says the "rendering of high dynamic range scenes is lacking accuracy", "white balance is inaccurate in some situations", the camera shows "significant sharpness instability in low light conditions", there is a "loss of detail and strong noise in low light" and "clearly visible fringing and color shading" can be observed in the images when shooting outdoors.
In video mode the HTC One M8 displayed "good noise reduction" but "white balance is often inaccurate", there is "no video stabilization", "no continuous autofocus" and "visible steps in luminance during exposure changes" can be observed.
Color, Exposure and Contrast
The DxOMark team found that the HTC One M8 images show "nice and pleasant colors outdoors." However, "some outdoor images of high dynamic range scenes lost a lot of detail in dark area", "white balance is inaccurate in some situations" and there is "visible color shading outdoors and in low light."
Overall DxOMark awarded the HTC One M8 scores of:
*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 the HTC One M8 shows "low luminance noise in bright light conditions" but also "strong sharpness instability between shots in low light conditions" and a "loss of detail and strong noise in low 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 that can be blurred away by noise reduction or obliterated by excessive sharpening (such as fine foliage, hair or fur).
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.
Note: Acutance is a single value metric calculated from a MTF result. Acutance is used to assess the sharpness of an image as viewed by the human visual system, and is dependent on the viewing conditions (size of image, size of screen or print, viewing distance). Only the values of texture acutance are given here. The measurements are expressed as a percentage of the theoretical maximum for the chosen viewing condition. The higher the score, the more details can be seen in an image.
For all DxOMark Mobile data presented on connect.dpreview.com we're only showing 8MP equivalent values, which gives us a level playing field for comparison between smartphone cameras with different megapixel values by normalizing all to 8MP (suitable for fairly large prints). DxOMark also offers this data for lower resolution use-cases (web and onscreen). For more information on DxOMark's testing methodology and acutance measurements please visit the website at www.dxomark.com.
Edge acutance is a measure of edge sharpness in images captured by the phone's camera. Again we're only looking at the most demanding of the three viewing conditions that DxOMark reports on - the 8MP equivalent.
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
DxOMark engineers don't just point camera phones at charts, they also take and analyze scores of real-world shots and score them accordingly. Their findings for the HTC One M8 were:
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 HTC One M8 are shown below:
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 HTC One M8 is trailing slightly behind most of the competition in the high-end bracket. The overall score is 79/100 in bright light and 74/100 in low light.
DxOMark scored the HTC One M8 71/100 overall for its flash performance which is lower than most of the competition in the high-end smartphone bracket.
Overall DxOMark Mobile Score for Photo: 70 / 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. Bottom line: DxOMark found the HTC One M8's overall video footage to show good texture and noise reduction but a lack of stabilization means footage can be shaky and there is visible brightness stepping when the exposure changes during recording.
Overall DxOMark Mobile Score for Video: 63 / 100