Quote Originally Posted by Caipré View Post
And if I may ask, what is the main advantage of a 35 or 85mm prime? For most situations, the same shot could be taken by moving forward or backward with the 50mm, correct?
Absolutely NOT!

See, the focal length only affects the magnfication of the image you are seeing. Moving position changes perspective.

For instance, imagine a beautiful scenic view, with mountains and a huge thundercould behind it and all that "glorious" jazz. If you were to move closer to that mountain the near-far juxtaposition (the relationship between the mountain and the cloud) would radically change.

So, you'd want to get a telephoto (85mm+) to magnify that view to fill your frame, from that perspective. The same image would be in your shot if taken with a 35mm lens, but it would be much smaller, requiring more magnfication upon printing and thus, more grain, etc.