A number of sites have linked to this article about depth of field, which looks at the commonly held belief that zooming in creates a shallower depth of field.
The article isn’t super clear, but the essential fact is that zooming in doesn’t actually change depth of field, it just makes the stuff in the background bigger. The stuff is no more blurry, it’s just easier to see the blurriness.
He’s absolutely right of course, but it’s really splitting hairs. In the end, it doesn’t really matter.