The Samsung Galaxy S9 feature san industry-leading aperture of F1.5. This will help to significantly improve the low-light performance of the phone, contributing to incredible picture quality and videos when shooting at night or in dark areas.
Just for comparison, an F1.5 aperture lens allows 1.44x times more light compared to an F1.8 aperture lens. It provides a 2/3-stop advantage, which of course translate to a better low-light performance.
Comparing an F1.5 lens of the S9 to a f/2.0 lens, the F1.5 lens provides 1.78x times more light, again, substantially delivering better low-light performance (considering all the other specs are the same). Of course when we compare to cameras from different phones we also need to consider the differences in the sensor, pixel size, optics, image processing and other factors. What I am talking about here is just about the lens aperture, the hole in which the light passes through to the lens to reach the sensor.
So let's check out how it compares to other leading flagship smartphones. Let's take the iPhone X for example. The iPhone X feature dual lenses for the main camera. The widest angle is the fastest of the two with F1.8 aperture compared to f/2.4 of the 52mm (35mm equivalent) lens. So as I mentioned above, the Samsung Galaxy S9 rear-facing camera will be able to obtain 1.44 times more light compared to the iPhone X wide-angle lens.
Now let's compared it to the Samsung Galaxy S8. the Galaxy S8 features a 12MP 26mm (equivalent) f/1.7 aperture lens. It's roughly 1/3-stop slower than the S9 F1.5 aperture lens. In other words, this means that the Galaxy S9 main camera with F1.5 collects approximately 1.3 times more light compared to the Galaxy S8.
The LG V30 features an F1.6 aperture lens. Here the difference is less substantial, because the Galaxy S9 F1.5 lens has only approx. 1/3-stop advantage and obtains 1.138 times more light compared to the LG V30.
Still, it's important to remember that there are other camera and hardware features that impact that low-light performance. However, this fact make me feel very optimistic, and I think we are going to see a low-light king here with the introduction of the Samsung Galaxy S9 and S9+.