When photographing a all black engine the first rule is to take off the 1A filter that increased contrast. It was best done with panchromatic film but now color film is being used, but sadly most is too high in contrast. Very good Digital will have much greater laditude to get the different shades of black, and gray. Most color film will give you a black glob, and then many in photography today never saw the kind of film which we used to use. Plus X Pan, or Tri-X. Few here will ever use a 4x5 again, I guess. And then there are those which will compress or stretch out the perspective so it will look like some weird art and not be a photograph representation of the passing. Publications can not use telephoto distorted photos as they will not fit/match in layout next to a proper photo with normal lense focal length. 50mm or 35mm film, 128-135mm for 4x5 film. A true photograph is one which gives a print in the same perspective similar to how your eye and brain sees the image. Match it!