Why can cameras capture buildings being destroyed when nuclear weapons explode?

There are several people in a group who are responsible for installing equipment to take pictures of mushroom clouds and using photoelectric devices to remotely control machines. As soon as the light radiation from the nuclear explosion comes, the machine will automatically start shooting; it is responsible for calculating the specific intensity of the light radiation, thereby adding or subtracting appropriate filters for the camera; but it is the most difficult and dangerous task of capturing the nuclear explosion effect. During the nuclear test, the working group was ambushed in the 720 area of ??the test site, which is an underground command post 720 meters away from the center of the explosion. During the nuclear test, the earth shook violently, but he held his breath and prepared for the attack. Ten minutes after the explosion, the command issued an order requiring him to start snapping pictures immediately. Putting on heavy chemical protective clothing, holding a dozen kilograms of Alai cameras, he jumped out of the ground, took an off-road vehicle and immediately pounced deep into the heart of the explosion. The road was bumpy, but the car was going fast. Entering the core of the explosion, the scene was shocking: tanks, locomotives, small buildings were set up, and some monkeys and plants were placed. However, under the huge energy damage of light radiation and shock waves, they had long been distorted and changed beyond recognition.