DPReview essay how equivalence in both field of view, and depth of field, is important in describing lenses across incompatible mounts/sensors. The following comes from the third page:
“As you can see, the real-world examples bear-out the expectations to a pretty good degree - when set to ‘equivalent’ apertures, the background blur is very similar. It also helps illustrate the distinction between background blur and depth-of-field - the background dots have all been spread to a similar degree, suggesting the same depth-of-field, but the appearance of them varies, depending on lens design.
In this instance, the lens on the 1”-type sensor is producing more concentrated blur circles - making them appear darker. This suggests the lens exhibits lower levels of longitudinal chromatic aberration than the others, such that different colors are being focused at the same depth. This would explain why the blur circles are less spread out and why they appear black, rather than the more diffuse, green-tinged rendering the other three lenses are offering.”
If only DPReview had showed price/size variability between equivalent lenses, which rarely favours of small-sensor cameras.