[Brightcolours]

We will not get on the same line. Two different cameras remain different, no matter what and how you up- or downsample images. In my opinion this is the worst idea to compare systems. Comparing a Minox 8×11mm with a Hasselblad 56×56 mm: What do you gain by sampling up or down until something fits to something else by just putting one of those systems out of it's proportions? You loose the advantages of one system for the benefit of another. There are and always were projects for which one system suits better than another - what good is a tripod based large format camera, when you want to do a reportage and want to remain mobile? How succesful one could blow up a DX-picture, no matter what MP or ISO to get a highly detailed view inside of a church?

 

Shrinking an oceanliner to the size of a canoo makes no sense at all to me. Different cameras for different tasks, but feel free to go on with equivalenting pears to bananas. I consider that useless and also totally ignoring the idea of creating pictures, it's just a tool. I would not take a watchmakers little hammer to demolish a wall, although it might be possible.

Understanding lens equivalence, what do you gain from it? The simple understanding of the simple facts that enable you to get a certain result with different equipment. 

 

There are only three variables that determine the image. Field of view. Depth of field. Exposure time.

And you want to argue that it makes no sense to understand these three simple variables across different formats? Ok...

 

And of course, a small camera is easier to put into a pocket. A FF camera with the appropriate lens is capable of very shallow DOF. A large format camera may have the edge for extremely high resolution requirements. 

 

It still makes sense to see what are equivalents across formats. ESPECIALLY when we are looking at an APS-C mirrorless camera from Fuji with an expensive, relatively large f2.8 zoom.

Handy to know that that is equivalent to a 70-200mm f4 L IS USM on a Canon EOS 6D, or a Sony 70-200mm f4 OSS on a Sony A7 II.

 

Also makes sense when someone has like a Canon EOS 100D and wonder if there is any way to get similar looks to images when they look at someone else's work, someone with deeper pockets and more professional equipment, like for instance a portrait or wedding photographer who is using a Canon EOS 5D mk III with a Canon EF 135mm f2 L USM lens. It is nice for that Canon EOS 100D owner to understand that he can get similar image parameters by understanding that for instance a Samyang 85mm f1.4 will get him close to the same FOV and DOF, even with his smaller camera.

 

Or, indeed, it is nice to know for Fuji X MILC owners that they can get similar DOF and FOV from their Fuji X-T1 with Fuji 56mm f1.2 lens as for instance a Sony A7R II user gets with a Sony Zeiss Batis 85mm f1.8. So that Fuji photographer does not have to run out and empty his pocketbook on that Sony + Zeiss, for similar images.

In short: I have no idea what you have against lens equivalence. It is simply theory based on facts, science and optics, does not pose confusion, and makes things very simple to understand. 

 

And  (real) photographers have always used this equivalence understanding when dealing with different film formats. They have understood equivalent focal lengths for similar FOVs, they have understood equivalent f-values for similar aperture sizes (DOF), they have understood the relation to film sensitivity and exposure time and the relation to film sensitivity and formulation to grain size and film resolution.

They could both pick the best tool for the job, AND make do with the tools at hand, to get the results they were after.