>>300205Okay did some more thinking. When you label a lens with its true focal length, you're actually truthfully describing a physical property of the lens. Great.
If you put on the 35mm equiv, then that description is only useful as long as people continue to think in those terms - which is a really recent development. It is an arbitrary choice based on the inability of idiots to really understand what goes on with lenses and field of view.
So given that we can't know the field of view just by knowing the focal length of a lens, what knowledge do we gain by accurate focal length reporting? Depth of field properties come to mind.
In conclusion:
- Reporting with 35mm equiv: Helps dumb people figure out FoV
- Reporting with true focal length: Clearly describes FoV for most people. Provides DoF info that is otherwise unavailable. Therefore all the benefits + more of 35 equiv.