[speakeron]

For the same field of view, a smaller sensor requires a decrease in the focal length; this leads to a greater depth of field. Moving to a medium-format camera will give less depth of field (and a large-format camera even less). Different sensor sizes using the same focal length will give the same depth of field, but the field of view will vary.

This explains it nicely: https://fstoppers.com/education/understanding-how-sensor-siz...