Samsung Galaxy Note 4 camera review

DxOMark Mobile Report

Summary

With a DxOMark Mobile score of 83 the Samsung Galaxy Note 4 currently takes the number two spot in the DxOMark smartphone rankings, placing it just behind its brand new cousin, the Samsung Galaxy S6, and in front of Apple's flagship device, the iPhone 6 Plus.
The DxOMark team reports the Galaxy Note 4's images show "good exposure both indoors and outdoors, overall good colors, very good detail preservation across the frame" and that the "autofocus is accurate and smooth". On the downside, there is "some noise in low light conditions" and the camera "often refocuses for no apparent reason".
In video mode the Note 4 footage shows "good detail and low noise" and is well exposed. However, "color shading is noticeable and stabilization artifacts are visible".

Still Photography

Color, Exposure and Contrast

The DxOMark team found that the Galaxy Note 4's images show "good exposure both in indoor and outdoor shooting, vivid, pleasant and realistic colors in all lighting situations, and overall good white balance". However, "in some high-contrast scenes, the images can be slightly burnt out.

Overall DxOMark awarded the Samsung Galaxy Note 4 scores of:

• 4.5 out of 5 for Exposure
• 4.5 out of 5 for White Balance accuracy
• 3.5 out of 5 for Color shading in low light*
• 4.3 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 on the Galaxy Note 4  "detail preservation is very good across the image" but "some noise is visible 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 (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.

	A dead leaf pattern is designed to measure texture acutance. It's 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 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 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.

Luminance texture acutance is slightly higher under daylight than under tungsten illumination.

In terms of texture acutance, the Note 4 beats the Google Nexus 6 and iPhone 6 Plus but cannot quite keep up with its new cousin Galaxy S6.

Edge Acutance

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.

In terms of edge acutance the Galaxy Note 4 beats all of its closest rivals.

The Note 4's ability to retain sharp edges is excellent across all light levels.

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 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.

In our comparison only the Galaxy S6's visual noise levels are lower than the Note 4's.

Noise levels in tungsten light are low across all illumination levels.

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 Samsung Galaxy Note 4 were:

Natural scene

• Texture (bright light): 4.8 out of 5
• Texture (low light): 3.6 out of 5
• Noise (bright light): 4.2 out of 5
• Noise (low light) 3.0 out of 5

Bright light sample shot.	Low light (20 Lux) studio shot.
100% crop: very good detail across the frame	100% crop: some noise but good edge detail

100% crop: still good detail

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 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 Samsung Galaxy Note 4 are shown below:

• No noticeable color fringing
• Almost no noticeable ringing
• Non-uniform sharpness in the field

Perceptual scores

• Sharpness 3.8 out of 5
• Color fringing 4.5 out of 5

Measured findings

• Ringing center 13.7%
• Ringing corner 5.7%
• Max geometric distortion -0.3%
• Luminance shading 8.6%

Distortion and Chromatic Aberrations

The graph shows the magnification from center to edge (with the center normalized to 1). The Samsung Galaxy S4 shows slight pincushion distortion, which you are not going to notice in normal photography.

The Note 4 shows some lateral chromatic aberrations which won't normally be noticeable in images.

Autofocus

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 Samsung Galaxy Note 4 does very well in this test. The overall score is 90/100 in bright light and 83/100 in low light.

Pros: 

• Autofocus is accurate and smooth
• Very little overshooting

Cons: 

• Scene change detection is slow
• The device often refocuses for no apparent reason

Autofocus repeatability - average acutance difference with best focus: low light 3.67%, bright light 1.94%

Flash

DxOMark scored the Samsung Galaxy Note 4 85/100 overall for its flash performance which is one point higher than the Galaxy S5 and two points lower than the Galaxy S6.

Pros: 

• Good detail preservation, accurate white balance and color preservation (without additional light source)

Cons:

•   Some white balance errors under tungsten illumination 

Overall DxOMark Mobile Score for Photo: 83 / 100

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Video Capture

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 Samsung Galaxy Note 4's video performance to be good, with images showing good detail and low noise but some stabilization artifacts. 

Pros: 

• Good detail and very low noise levels
• Images are well exposed

Cons: 

• Color shading is noticeable
• Stabilization artifacts are visible

Overall DxOMark Mobile Score for Video: 83 / 100