Smartphone camera sensors are too tiny compared to DSLR or mirrorless camera sensors. A DSLR/mirrorless camera with APSC size sensor is about 20-30 times larger than the sensors found in smartphones which corresponds to far superior light collecting capability of APSC sensors. Photography relies more on physics of light than software and electronics, if a sensor is not able to collect good amount of light, software/electronics will not be able to help us to create good quality images. The amount of light received by camera sensors depends on aperture size and exposure time. Aperture size on a smartphone is fixed, left only exposure time to determine image quality. Also, smaller sensors produce images with more noise and more grainy. Exposure of 30 seconds shutter time is enough to capture the details of night sky including the Milky Way, but often the noise ruins it all due to small sensor size on smartphones. To create a night sky image that matches the noise level of image from APSC sensor, image stacking technique comes in very handy in reducing noise. I usually take 10-20 exposures with 30 seconds each (total exposure of 5 to 10 minutes) and apply image stacking with either Photoshop or DeepSkyStacker.
*Drag the slider to view the difference.
Image on the right above is a stacked of 17 exposures. It improves signal-to-noise (SNR) by ~4 times and more details from the Milky Way can be recovered.
Single exposure vs Stacked of 16 exposures
Meteor Shower Effect
Other than creating cleaner images, 10 minutes of exposure is enough to create star trails. The images can be stacked by using StarStaX application to create meteor shower effect on stars. 10 minutes might be short for a good star trails image, but it looks fine with comet style star trails. StarStaX is relatively easy to use compared to Photoshop, there is a Comet Mode option to customize the direction and length of star trails.
