Because a filmmaker has control over the film making process, he or she can communicate many things through the type of film he or she uses. We need to keep in mind that as much as the content is a conveyor of information, the form of something also conveys meaning. So, if a filmmaker decided to shoot a modern film in black and white with lots of graininess, then he or she would convey a sense of age. The reason for this is simple; black and white films speak of an earlier age. Or we can say that black and white films connote something different.
For example, Schindler's List came out in 1993, and it was shot in black and white with a good amount of visible noise. This was a very intentional decision. It looked like you were watching a documentary. It achieved its purpose. We were made nearly eye witnesses of the horrors of the holocaust.
More recently, in 2007, the movie 300 appeared, which was about the historic battle of Thermopylae. It was shot mostly with a super-imposition chroma key technique. This made sense, because originally 300 was a graphic comic. Hence, by shooting it in this way, the movie had overtones of the comic genre.
In summary, the way a filmmaker shoots a film conveys different expectations to an audience.