Mikael, I've explained enlargement multiple times.
But I'll give it yet another whack. Why not?
Let's say your client has hired you to photograph his sailboat tied to the dock at sunset, and he wants you to make a 48" x 72" print.
If you use a 135 format camera, such as a 5DIII, the image recorded on the sensor will have to be enlarged roughly 50 times to make said print. If you use an 8x10 view camera, the image will be enlarged about 6 times.
Let's say your view camera has a low-resolution sensor that is all of 500 ppi, making it an effective 20 megapickles -- slightly less than the 5DIII's 22 megapickles.
Also assume you're using a 50mm lens on the 5DIII and a 400mm lens, so both have the same field of view. And assume you're shooting the 5DIII at f/8 and the view camera at f/64, so they both have the same depth of field. And even go ahead and assume that you're shooting the 5DIII at ISO 100 and the view camera at ISO 6400, so the shutter speed is the same. For the sake of this discussion, also assume that the technology is comparable for both -- the sensors are the same generation, the lenses are both superb, and so on.
So, two setups almost identical. On the one hand, we've got a 22 megapickle 5DIII at ISO 100; on the other, a 20 megapickle view camera at ISO 6400. Same depth of field, same shutter speed, same framing, same everything else. And, at the end of the day, the same 48" x 72" print.
What, if any, difference do you think there will be between the two prints, and why?