Task: Question Answering
Input (English): Context: If you are a traditional traveller who believes cameras are irreplaceable,here are some things you should pay attention to when looking for the perfect camera. Sensor size Along with the megapixel count,the size of the sensor dictates the general image quality as well as the camera's performance in low light. It also determines whether the camera can electronically put the details it captures bigger enough to see--which is what makes the pictures not clear enough to see when you view the photos on a bigger screen. Portability "The important thing is that the camera isn't too big or heavy,and that you have a good zoom range for both wide-angle and telephoto shots ,"Atherton told CNN.A good choice would be a slim,light pocket camera with a high-qualified built-in optical zoom. "These are very popular for travel as they are light,but built with a telephoto lens that can zoom up to 60 times," Atherton said. Zoom and shutter speed For action or crowd shots,a fast shutter speed is a key factor. "When dealing with anything that's active--wildlife or people in action on the street--faces change within a tiny part of a second," said Arnold,"a fast shutter speed is helpful in shooting the several hundred photos you might need to get that single winning shot." 
 Question: What will contribute to a satisfactory photo of a running lion in the wild?
Output (English): the shutter speed.