It’s only the focal length and f-stop that affect depth of field. Sensor size affects it only indirectly, because you need a different focal length to get the same angle of view.
replyFrom an optical point of view, light does not bend differently just because you put a differently-sized rectangle somewhere in its path. Or to put it another way, if you cut the edges off your sensor, that won’t alter the image on the remaining area of the sensor.
Yeah I guess you're right but there are limits on how shallow your DOF can get on smaller sensors. So when it comes to practical irl results you kinda need a larger sensor to get extremely shallow DOF.
reply> there are limits on how shallow your DOF can get on smaller sensors.
replyOnly in the sense that you generally use a smaller sensor because you want your camera to be small.
If you take a full frame SLR and attach a 100mm f1.8 lens to it, you’ll get a shallow depth of field. Now crop that image down to an area of the sensor corresponding to the size of a phone sensor, and the cropped image will have the exact same depth of field.