Why low light is a problem
Size is the problem. The light-sensitive area in most sensors that are integrated in smartphones is roughly 15 to 30 mm². In comparison: Full-format image sensors from our editor’s DSLR camera have an area of roughly 860 mm². That is 30 to 60 times more. While small smartphone sensors can gather enough light during the day. The chip simply receives too little photons in the dark. However, there are now several ways that phones take a bright picture.
Whether you’ve tinkered around with ISO values before or not: you must have encountered the term at some point. To produce a bright picture in low light, you can simply amplify the image sensor’s light sensitivity. The camera app does this by itself when taking pictures in automatic mode.
However, greater ISO sensitivity also produces greater read errors. That manifest themselves as image noise, loss of detail and washed colors, among other things. In short: The pictures are indeed bright and mostly sharp, but they’re not really presentable most of the time.
If your smartphone doesn’t let you manually adjust ISO sensitivity, there are different apps you can use instead. Camera FV-5 Lite(Android) or Pro Camera (Apple), for instance, offer numerous settings options. Unlike the iPhone, however, most Android smartphones and their camera apps offer numerous manual options.
More light is required to keep the sensor sensitivity low (and hence also reduce image noise). As silly as it may sound, this can be achieved by adding sources of light to the subject. The smartphone’s integrated photo LED is always available here. Many modern phones even have several LEDs to adjust the flash’s light color to the environmental lighting. It’s quite effective at preventing color casts and the images look decent.
However, these integrated camera LEDs also have their drawbacks. The flash from the camera’s line of sight eliminates all shadows. Often making the subject look very two-dimensional and even “flat”. Therefore, the integrated flash should only be used when absolutely necessary.
In most cases, however, there are other options to ensure more light. If you take a picture of a moving object, then the location changes. When taking a portrait, take a few steps over to the nearest street lamp. Take all steps to ensure that light does not come directly from above to the greatest extent possible. Since that causes awful-looking shadowing on the face.
Longer exposure time
If you can no longer add any light to the subject, then you must give your smartphone more time. A longer exposure time lets the image sensor “see” the subject longer and gather more photons. As well as brighter photos, it also has an additional effect: Anything that moves is blurry. In the worst-case scenario, it causes blurry shots. But it also for example, it turns passing cars into long trails of light.
To increase the exposure time, you need the manual mode, often called “pro mode” or something similar. This questionable option is called shutter speed, exposure time or is simply and poignantly abbreviated with “S”. Most smartphones in automatic mode take pictures at a maximum speed of 1/10 second. Longer exposure times require you to keep your hand very very still or else the shots will come out blurry.
Passing trams and cars or fireworks in the sky turn into beautiful traces of light at two to eight seconds. To depict a landscape illuminated by the moon, you may need to use a 30-second exposure time. Which is the maximum in many camera apps. If the images turn out too bright at longer exposure times, you must ensure that the ISO sensitivity. Is set to “automatic” or to a low value. If that doesn’t help, then the subject is quite simply too bright. And you need to correct it by decreasing the exposure time.
Of course, for long exposure times, it’s extremely important that the smartphone does not move during the shot. To do this, you can either fix or lean your phone on something, or use an accessory, which brings us to our next point.
Anyone who finds nighttime photography fun and regularly takes shots in the dark should probably consider one accessory: a tripod. Since smartphones are light and compact compared to full-fledged cameras, the same applies to the tripod as well. For instance, you can obtain a small Gorillapod for less than $15 or you can get the Gorillapod and a corresponding smartphone universal adaptor for $20. Both objects together fit comfortably in your jacket pocket and are ready to use in a few seconds.
Sony also gets another bonus point: Most smartphones from the Japanese company have a particularly flat bottom, so they can sit on their sides without requiring extra accesories for long exposure times.