I have rented / borrowed enough equipment over the years that I have come up with a template for comparing the borrowed / rented gear to something I already own. Even if the gear happens to be NOT in the same league as what I already have got.
Usually it is a new lens or camera that I am trying to “compare”, so I pick a similar lens or camera that I already have as the base.
I had rented the Nikkor 105mm f/1.4 recently and though I didn’t exactly take the time to take some comparative shots, if I had the time here is what I probably would have done (or tried to do).
- use my 70-200mm f/2.8 as the base, since 105mm is a setting that I can put my lens at
- use my D700 as the Camera (since my goal is to compare the “lens”)
- find some lowlight scenes to take the comparative shots