Talked to a special effects guy on a set once years ago. They were shooting for a TV show, and the shot required things to look hazy. The amount of artificial smoke that was pumped into the room was so thick you couldnt see the other side of the room, and it was a big room, about the size of a movie theatre. The special effects guy told me the camera will only pick up the smoke that is within the cameras focal range, and much more was needed than what the human eye picks up live to create the right effect. Although we could barely see across the room, he said the final shot will look like a nightclub or bar where poeple are smoking. I was surprised.
I am not sure but maybe the optics on a tank work the same, and only the smoke within the focal range is seen. ???