Some things should move when panning.
When taking a picture of a moving vehicle, you want the wheels to be movement-blurred. Nearly everything you are panning should be sharp, but some things still need to move. Here’s how to work through the problem.
Examine the picture above. The wheels are slightly blurred. At around 40 miles per hour they should really have been blurred to appear real. The problem is finding the right shutter speed. Two low and your panning technique is lost to blur. Too fast and the subject freezes.
Here’s how to fix it. Get comfortable panning for the main subject, say, a car. Try a few panning shots to get it sharp. When you have that right, slow the shutter speed down by one third of a stop (one click on most DSLRs). Do the wheels look blurred? No? Try again. If the wheels still have no movement blur, turn down the shutter speed. Shoot and check for wheel blur.
If you have to turn down the shutter speed a lot, you were panning with shutter speeds starting too high. Normally one or two clicks down finds a point where the wheels will blur.
This works with most panning subjects. When photographing a running man a little leg blur is great. Track the body, get that sharp with your panning. Next run, turn down the shutter speed. If the legs are not slightly blurred, do it again.
You have to practice to get it right. This technique, progressively slowing shutter speed, will get the speed right. Soon you will judge your starting shutter speed better. Then, one or two adjustments and you get movement blur that looks good.
If you cannot pan without blurring your main subject, reverse the idea. A faster shutter speed will make it easer to get sharper panning on your main subject. Practice and adjustment is the key.
Read this article with the other panning articles. Good panning comes with practice and knowing what shutter speed suites your favourite subject.