How We Test Smartphones And Tablets

By Matt Humrick
published

Today, we outline the strict testing procedures used to obtain accurate data and discuss each test that we perform on smartphones and tablets.

Camera Performance And Photo Quality

Photo quality is composed of many facets, including exposure, white balance, sharpness, and noise to name just a few. There are also many variables that affect these qualities, including hardware (lens system, CMOS sensor), software (noise reduction algorithms), and environmental conditions (light level, light color, scene contrast). Clearly, photo quality is a complex topic, making it difficult to measure.

Our current method for evaluating quality involves taking a series of pictures and subjectively comparing them to photos taken with other competing cameras. The pictures are taken in a variety of lighting conditions, capturing scenes our users might encounter or that present a challenge to the cameras. To help ensure that the conditions for each photo are similar, the photos for each camera are taken from the same spot and all at the same time (within a two to three minute window). The stock camera app and default settings are used for all images except where noted in the review.

Matt Humrick
7 Comments Comment from the forums
  • blackmagnum
    Thank you for clearing this up, Matt. I am sure us readers will show approval with our clicks and regular site visits.
    Reply
  • falchard
    My testing methods amount to looking for the Windows Phone and putting the trophy next to it.
    Reply
  • WyomingKnott
    It's called a phone. Did I miss something? Phones should be tested for call clarity, for volume and distortion, for call drops. This is a set of tests for a tablet.
    Reply
  • MobileEditor
    It's called a phone. Did I miss something? Phones should be tested for call clarity, for volume and distortion, for call drops. This is a set of tests for a tablet.

    It's ironic that the base function of a smartphone is the one thing that we cannot test. There are simply too many variables in play: carrier, location, time of day, etc. I know other sites post recordings of call quality and bandwidth numbers in an attempt to make their reviews appear more substantial and "scientific." All they're really doing, however, is feeding their readers garbage data. Testing the same phone at the same location but at a different time of day will yield different numbers. And unless you work in the same building where they're performing these tests, how is this data remotely relevant to you?

    In reality, only the companies designing the RF components and making the smartphones can afford the equipment and special facilities necessary to properly test wireless performance. This is the reason why none of the more reputable sites test these functions; we know it cannot be done right, and no data is better than misleading data.

    Call clarity and distortion, for example, has a lot to do with the codec used encode the voice traffic. Most carriers still use the old AMR codec, which is strictly a voice codec rather than an audio codec, and is relatively low quality. Some carriers are rolling out AMR wide-band (HD-Voice), which improves call quality, but this is not a universal feature. Even carriers that support it do not support it in all areas.

    What about dropped calls? In the many years of using a cell phone, I can count the number of dropped calls I've had on one hand (that were not the result of driving into a tunnel or stepping into an elevator). How do we test something that occurs randomly and infrequently? If we do get a dropped call, is it the phone's fault or the network's? With only signal strength at the handset, it's impossible to tell.

    If there's one thing we like doing, it's testing stuff, but we're not going to do it if we cannot do it right.

    - Matt Humrick, Mobile Editor, Tom's Hardware
    Reply
  • WyomingKnott
    The reply is much appreciated.

    Not just Tom's (I like the site), but everyone has stopped rating phones on calls. It's been driving me nuts.
    Reply
  • KenOlson
    Matt,

    1st I think your reviews are very well done!

    Question: is there anyway of testing cell phone low signal performance?

    To date I have not found any English speaking reviews doing this.

    Thanks

    Ken
    Reply
  • MobileEditor
    1st I think your reviews are very well done!

    Question: is there anyway of testing cell phone low signal performance?

    Thanks for the compliment :)

    In order to test the low signal performance of a phone, we would need control of both ends of the connection. For example, you could be sitting right next to the cell tower and have an excellent signal, but still have a very slow connection. The problem is that you're sharing access to the tower with everyone else who's in range. So you can have a strong signal, but poor performance because the tower is overloaded. Without control of the tower, we would have no idea if the phone or the network is at fault.

    You can test this yourself by finding a cell tower near a freeway off-ramp. Perform a speed test around 10am while sitting at the stoplight. You'll have five bars and get excellent throughput. Now do the same thing at 5pm. You'll still have five bars, but you'll probably be getting closer to dialup speeds. The reason being that the people in those hundreds of cars stopped on the freeway are all passing the time by talking, texting, browsing, and probably even watching videos.

    - Matt Humrick, Mobile Editor, Tom's Hardware
    Reply