What is the difference between the fidyah (expiatory payment) for fasting and the kaffarah (atonement) for fasting?

The expiatory causes (kuffarah) in fasting are two: Sexual intercourse during the daytime of Ramadan intentionally, and its expiation is freeing a slave. If one cannot find a slave, then fasting for two consecutive months. If one is unable to do that, then feeding sixty poor people. The second cause is delaying the making up of missed Ramadan fasts until another Ramadan begins, and its amount is one mudd (a measure of food) for each day, in addition to making up the fast.

The causes for paying a ransom (fidyah) are two: Inability to fast Ramadan due to an illness from which recovery is not expected, or old age. The second is for a nursing or pregnant woman who fears for her child only. The amount of the fidyah is one mudd of food for each day, and the pregnant and nursing women must also make up the fasts.