Smart Capture mode is optimized for Action capture with high FPS (Frame Per Second) capturing. It is a camera mode optimized for capturing moving objects.
There are basically two reasons why Smart Capture mode can't perform as good as single-frame capture in low light:
- Smart Capture does not run through the same IQ-improvements. It’s too slow and would cause a very long saving time for each image sequence.
- Smart Capture mode does not allow long exposure time. It is limited max shutter time to 1/66 of a second to make moving objects sharper.
- Single capture in Lumia 920 and Lumia 925 phones allows for long exposure time, which allows more light to come in to the sensor but will also result in very blurry moving objects.
The downside of having short max shutter time and fast saving/transferring of the shots is a lower image quality. Which is more visible indoors. The max resolution of Smart Images has been lowered to 5MP to lower the max file size of the shots a bit.