# Smartphone

A smartphone is a portable device combining functionality of many solid-state everyday life tools in one unit, including digital camera, camcorder, flashlight torch, music player, book reader, web browser, messenger, radio, environmental sensors like air pressure, and more. The functionality varies among models.
Supplementary to the Wikipedia article, this resource documents tips and guides on usage.

## Charging port care

To prevent unnecessary wear on the charging port, connector, and cable endings, grab the handle and not the cable. The two handles are between cable and the metal pieces that enter the port. Push or pull the connector perpendicularly to the charging port without applying sideways pressure that could wear down the connector and port faster.
Slightly and alternatingly moving the connector sideways in parallel to the USB connector's flat surface (longer edge, horizontally to the charging port) is harmless and could facilitate connecting and disconnecting, whereas downward pressure (vertically to charging port against the connector's longer edge) is unhealthy for the connector endings and should be prevented.
Inserting a more worn charging connector wears down the phone's port less, since it requires less insertion force, but has a higher likelihood of undesirably disconnecting.
Wearing down the charging port can be limited through wireless charging. While more convenient, it is slower and produces more heat than wired charging due to the lower efficiency of wireless power transmission. As such, wired charging is more suitable in a hurry.

## Battery care

Battery care is of increasing concern as a result of the popularization of designs that deny its replacement, typically the shortest-lived component of the unit.
Signs of an expiring phone battery are quick battery drain and system outages caused by voltage starvation.
In order to delay the battery expiry, stress to it needs to be limited by foregoing fast charging to the extent possible, as it causes heat that stresses the battery, and the operational battery capacity needs to be limited to a centered range between approximately 25% and 75%, as too high and too low charging states wear it down faster. If no automated process is able to limit the charging state, the power needs to be disconnected manually at a charging state of around 70 to 80 percent, as well as be recharged in time to prevent drain below 20%.
The smartphone can optionally be cooled using a portable external USB-powered fan. This both extends the life span of the battery and might increase charging speed if it was throttled by an overheating protection mechanism.
Possible measures to reduce power consumption include deactivating connectivity features such as WiFi and Bluetooth when unneeded, and monitoring background apps' activity. Note that some tasks such as using cellular internet and high-definition video recording inevitably consume much power. Consider bringing an external battery bank ("power bank") with you.
When exposed to cold temperatures which could occur during the winter season, a smartphone might power down as a result of the cold temperatures slowing down the chemical reactions in the battery cell, causing an undervoltage condition. Smaller and older batteries are weakened more by cold temperatures. If no external power source is available, it is recommended to warm up the smartphone for a few minutes using your body.

## Physical protection

It is recommended to use both a protective case and a screen protector. Even cheap ones provide significant protection compared to none, and are far cheaper and easier to replace than built-in smartphone parts should damage occur.
Smartphone cases may be equipped with useful features such as a kickstand.
When removing a smartphone case that is difficult to remove, apply pressure to either of the shorter shorter edges (i.e. bottom or top side from vertical view), since they are more robust against the pressure.

## Charging speed

Using a cable with low electrical impedance (resistance) may speed up charging. Cables rated to support higher currents such as 5 Amp. have thicker copper wires, thus less resistance. Longer cables (e.g. 3 metres) tend to have a higher resistance, though the thickness of the copper wires plays a more important role.
Charging protocols such as Quick Charge by Qualcomm and Pump Express by MediaTek, which use elevated voltages, are likely compatible with existing USB cables and don't mind long cables, but produce more heat in the end device due to necessary internal voltage downregulation.
Charging speed can be verified using a USB multimeter as depicted.

## Camera
### Controls

It has been widely established across smartphone vendors that focusing is done by tapping on an object inside the viewfinder, compensating the exposure value (brightness) is done by swiping up and down, and focus and exposure are locked by holding on the viewfinder for between half a second to a second.
After tapping on the viewfinder, a rectangle or circle usually denotes the focused position, and it might turn green when focused successfully and otherwise red. The exposure value might remain manually adjustable while focus and exposure are locked. Depending on the camera software, the availability of these gestures could be restricted in video recording mode, slow motion recording mode, and for the front-facing camera.

### Orientation

It is recommended to film horizontally and to avoid rotating the unit while recording.
Filming horizontally is recommended as the resulting footage will gracefully fill computer monitors' and televisions' screen surface, whereas vertical video appears as a slit.
Vertically filmed footage would need to be cropped or zoomed in to fill the entire screen, not only resulting in a lower-resolution crop of the video, but depending on video players' capability to do so during playback. Cropping in a video editor either requires time-taking rendering to a separate video, or sufficient processing power for real-time playback.
Orientation should remain constant throughout recording, as filming in a different orientation than when recording was initiated results in a misrotated picture. Counter-measures such as correcting rotation using metadata from the accelerometer or gyroscope have not been implemented as of 2021, and early future implementations might be proprietary (closed-source), thus not widely supported among video players.
To ensure photos and videos are saved in the correct orientation, first look at the user interface's elements. If their orientation does not match the desired orientation, which can happen shortly after launching or when pointing the camera nearly perpendicularly, tilt the device upwards for a short moment to correct the rotation assumed by the software.
Some camera software locks the rotation of the user interface elements while filming or warns the user about rotation.

### Resolutions

The camera software typically lets one adjust the resolution for photography and filming. A higher resolution produces better-quality images and videos, but demands more battery power and storage. Adjust the resolution based on the value of a moment.
If you are low on storage or battery charge, you might want to select a lower resolution to extend the remaining recording time.

#### The screen argument

   I don't have a 4K screen, so why should I film in 4K?
Not having a screen that matches the dimensions of a video resolution option is not an argument not to record in that resolution, since one might acquire such a screen in future, and higher resolutions still deliver a higher quality due to higher bit rates and chroma subsampling. In addition, higher resolutions allow for more magnification in later video editing, as well as extraction of higher-resolution still pictures. In simple words, if one wants the best possible 1080p (Full HD), one should film in 2160p (4K).
Even if a 2160p video is never watched on a 2160p screen, still frames can be extracted as standalone photographs. 2160p translates into over 8 megapixels, whereas a 1080p frame is just above 2 megapixels.
These benefits make video footage with a higher resolution more future-proof, meaning potentially more useful in the future.
The same principle applies to frame rates. While the only purpose of recording at high framerates such as 120 frames per second used to be slowing down the video to create a slow motion effect, screens with a refresh rate of 120 are becoming commonplace on mobile phones, so a video recorded at 120 frames per second in 2015 can be viewed at real-time speed for a smooth effect on a 2025 smartphone.

#### Purity

Since the software of smartphone cameras (and other consumer-grade video cameras) encodes the footage with a chroma subsampling scheme of 4:2:0, the colour information is stored at only at the quarter of the resolution as the brightness information, in order to compress far more efficiently with only a slight quality loss noticeable to the human eye. This means that 1080p Full HD video (1920×1080 pixels) only has 540p (960×540 pixels) of colour information, whereas 2160p 4K video (3840×2160 pixels) has 1920×1080 pixels of colour information, making it resemble pure 4:4:4 subsampling at 1080p. Due to the higher bit rate of 2160p 4K video, compression artefacts are less visible even when played back on lower-resolution screens.

### Microphones

Typically, there are two microphone holes, one located at the top edge and one at the bottom edge, to record spatial stereo audio while holding the smartphone horizontally for recording.
Make sure your hands do not cover the microphones of your smartphone while recording video, or the audio quality will suffer.

### Self-timer

In low light, a possibility to prevent shakiness is to make use of the self-timer.
Set a short time like two or three seconds (depending on which option exists in the software) so you can use this time to change your grip and posture to as steady as possible after pushing the shutter button.

## Settings

Device settings, also referred to as "Preferences", allow improving the convenience of your usage. Settings to consider adjusting, where available, are:
* Enabling the LED indicator during stand-by mode to facilitate finding and picking up the smartphone in dark environments. The LED may blink or stay on continuously. Its power consumption is marginal only, making no noticeable difference in battery endurance.
* Enabling alternative methods for waking up from stand-by, such as double-tap, which takes less effort than pushing the power or home button. Some smartphones may allow waking up through the proximity sensor, which is referred to as "air wake-up" by Samsung, but works while the device is not moving to prevent accidental detection. Smartphones may allow automatically waking up when picked up.
* Specifying applications to be launched with touch gestures detected while the device is in stand-by mode.
* Deactivating transition animations, as they cause inconvenient delays of inertia. These include transitions between menu pages, unfolding the quick control menu, opening applications, and opening the list of recent tasks. On the popular Android operating system and its derivatives, this option is found in the "Developer options", which first have to be revealed by tapping the "build number" entry in the device information menu seven times.
* Deactivating remote volume control by Bluetooth clients such as vehicle audio systems, to be able to retain manual volume control on the smartphone. On Android OS and derivatives, this is also found in the developer options.
* Smartphones may implement gestures recognizable during stand-by mode, also known as "off-screen gestures" or "screen-off gestures". Such may include double-tapping to wake up the device from stand-by mode without having to push any button, and drawing shapes to quickly launch applications such as the camera.

## Accessories

Various accessories could increase convenience and practicality, such as a kickstand case for watching video and typing (depending on angle), a cover, possibly one with preview display for quick assessment of notifications and messages and missed calls, a USB On-the-go adapter for plugging in USB flash drives, and a wireless charging station if supported.
Support for accessories varies among mobile phone models.

## Picking a smartphone

If you have difficulty deciding which smartphone to pick, ask yourself which desired functionality is missing from your current smartphone, and what your primary tasks are. If your budget is too low, weigh the importance of features against each other, and get the phone with the more important features.

## Decisions after purchase

You may wish to unlock the smartphone's bootloader in order to be able to "root" the device for administrative tasks such as creating full backups and advanced modifications. However, this may void the warranty. It is recommended to make that decision soon after purchase, as switching the bootloader state may require a full erasure of user data, which becomes increasingly difficult to back up with accumulation over time.

## Apps

It may be necessary to install multiple apps with a similar purpose, such as file managers, as they functionally may complete each other.

## Screenshots

Depending on implementation screenshots may be captured with a short press or an approximately second-long hold of a button combination. The former is preferable, as accidental shots are better than missed shots. Accidental ones can simply be deleted if desirable, whereas missed ones can not simply be recreated.

## Further tips

* Do not overrely on a smartphone's water protection. See it as a protection against accidents, but put it into an additional water-protecting case when entering water.
* Mobile browsers usually allow viewing pages' source code by manually typing view-source: before the URL.
* Before applying a screen protector, clean it thoroughly using a micro fibre cloth to prevent ugly marks from grains of dust.
* Depending on vendor and configuration, it may be possible to launch the camera quickly to prevent missing moments by pressing the home button or stand-by button twice. Some smartphones feature a dedicated camera shutter button, which may allow for quick launching through double-pressing or holding.
* You may choose to photograph and film at lower resolutions to extend the remaining number of photos and recording duration in the remaining data storage space.

## See Also

* Should batteries in portable electronics be replaceable?
* Wikipedia: Smartphone
* Wikipedia: List of open-source mobile phones