How does one adjust keyframe "smoothness" on the scaling attribute?

So if I have something that zooms in and out where the crop function just won't do because I need it to be really precise, I use the scaling attribute in the inspector. Unlike the position keyframes, there seems to be no way to turn smoothness on. It's always a hard start and a hard stop.

It is correct that the Scale attribute does not have ease-in/ease-out. To zoom in or out with smoothness I find the Crop attribute to be very precise. You have more control over the zooming then with Scale (you can adjust 4 individual parameters) and for extreme control you can hold the Option key when you drag on a parameter to increase or decrease its value in very small fractions.

- Ronny