The amount of blur is different from the depth of field. The blur depends on diameter of the entrance pupils, placement of subject relative to hyper-focal distance. With two different lens focal length, same depth of field can be achieved even if they have very different diameter of the entrance pupil. Most people confuse both. If I use a 200mm f2 wide open, there is no way you can achieve the same background blur with a
50mm lens because you would need a 50mm f0.25 lens which does not exist. And if you use a 500mm f4, there is no way you can achieve the same completely smooth background with a 85 f1.4 lens. Therefore there is a gap between formats that can only be close via stitching, and when stitching can't be done, it is wrong to say that two different format can produce the same result. That's physically not possible. Interesting to see people defying the laws of physics for emotional reasons.
---------- Post added 21-06-16 at 23:41 ----------
Originally posted by Qwntm So clearly FF is about 30-40% better at shallow depth of field shots, on paper.
Yes, thanks. You do the calculations on paper. Thanks for that. It's always good to nail it down from some references such as Cambridge in color.
Originally posted by Qwntm If you can't see the difference, who cares?
I can see the difference (beyond paper), I posted a link where people can see how photos are taken with a 5DIII and a 200mm f2.