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Math is on my side. Thus my ammunition is fairly powerful ;-)

 

True, but this topic manages in generating confused discussions in spite of that.   I think that the problem isn't math and how it's understood, but the lack of clarity, in some discussions, about all the factors that play a role - mostly the fact that to achieve the same framing you have to either change the focal length or the focal distance.

 

However, PERSONALLY I don't care too much about this topic. I have made my peace with small format systems long ago.

When carrying beasts such as a Canon EF 11-24mm f/4 USM L or Sigma 150-600mm Sports for an hour, I just know that this just isn't the place to be for me. It's fun for that single hour but then it's enough really.

 

With the partial exception of the 150-600mm ©, which anyway is a pain to carry on (yesterday I tried it with a 7km hike for the first time...), I agree. Nevertheless the argument is important because you're aware of the trade-off and you accept it. And since it's not only a matter of FF vs APS-C, since we are also offered with smaller sensors, knowing the thing makes one to precisely pick the trade-off which is fine for him. For instance, I accept the loss of DoF with APS-C, but not going further in that direction.