[defaultname]

"Your mistake"

There is no mistake. Your first paragraph is unfortunately founded on some misunderstandings of optics, however I calculated the hyperfocal length for an equivalent ASP-C 35mm system and an iPhone at the same crop (which anyone with an SLR and an iPhone can replicate in moments). The iPhone has a dramatically higher DoF. There are no mistakes in that calculation. This is the reason why you need computational bokeh. It's why it's so easy for everything to always be in focus. Could someone contrive ridiculous focal length / f-ratio / CoC parameters? Of course they can -- it's just a function with parameters that you punch in, and they can offset. In actual reality, however, short focal length is the primary input into why small cameras feature larger depths of field. Why we talk about the equivalent aperture in the way that we talk about equivalent focal length.

sudosysgen's argument in the end seems to distill down to "yes, but compare it via the equivalent DoF f-stop on the larger camera" which is a short circuit of the entire argument. It is basically saying that AMC is worth the same as Apple if AMC shares were each worth $4636.

Okay.

[sudosysgen]

That's not how it works. If I take a picture with 2x crop sensor at 100mm f/2 it is going to be exactly the same picture as at 50mm f/4 on a FF camera. Its just how it works. They have proven it using the DOF equation by showing that scaling the CoC factor down with the focal length and scaling the focal length down means you have the same DoF as long as the actual aperture diameter is the same, algebraically. I gave you an explanation of why it is the same because the solid angle is preserved. In the end you're making the typical photographer mistake of misunderstanding crop factor.