Google Pixel made a name for having one of the best cameras in the market. A recent Google experiment showed that with the right app, images taken with this phone can be made even more incredible.
Software engineer Florian Kainz of Google Daydream did an experiment replicating nighttime photos taken with a DSLR camera using only Google Pixel and Nexus phones. He wrote a simple camera app to manually control the camera's settings. The results were far from DSLR-like, but the experiment can pave the way for development of apps specializing in low-light photography.
The Challenge
Kainz shared his research via the Google Research Blog. There, he wrote that the experiment started as a dare from a colleague who challenged him to reproduce a photo of the Golden Gate Bridge taken with a DSLR. However, he must only use a phone, specifically Google Nexus and Pixel. Kainz and his then-colleague worked in Gcam, a research unit in Google that focuses on "computational photography," or the development of camera algorithms for smartphones and small cameras.
Kainz prefaced the experiment by saying that low-light photography apps like HDR+ rapidly shoots a burst of photos up to 10 exposures and stitching them together into one photo. However, the images are still not up to par with professional cameras given the technical limitations of present camera phones.
Issues like camera shake and focusing still persist; when it is too dark outside, the camera's focusing mechanisms, contrast detection, and phase detection fail to focus on the subject. Camera shake can ruin long-exposure shots, and the phone's small sensor picks up so much noise at low light (small sensor + high ISO = high noise/grain).
The Solution
To address these challenges, Kainz wrote a simple Android app to gain manual control over the camera's ISO, focus distance, and exposure time settings. What the app did was when the shutter is pressed, it took up to 64 frames in one burst.
With this app on a Nexus 6 phone, he took a photo of the Point Reyes Lighthouse in California under the light of the full moon. The phone took 32 four-second shots at ISO 1600. Then he shot 32 more black frames by covering the lens with a tape.
Then he post-processed the images using Photoshop by "computing the mean of all 32 frames cleaned up most of the grain, and subtracting the mean of the 32 black frames removed faint grid-like patterns caused by local variations in the sensor's black level." The resulting image, according to him, looked surprisingly good.
Despite clearly showing that the camera phones can be stretched to their limits to produce good nighttime images, the procedure still took a lot of tweaking. The experiment required a lot of post-processing, which can be a hassle for enthusiast photographers. But Kainz was optimistic that in the future, an appropriate app can process the images internally, which can make low-light camera phone photography a possibility.
