Drop test with load cell: longer impulse on load cell than optically
Any real-world system has limited speed. So, that something that is very fast (optics) measures a short event "shorter" than a slower, mechanical system isn't surprising at all.

If your sensor is linear, then you can model the slowness and "memory" effect by what we literally call an impulse response, being convoluted with the input signal (which, in your case, is the force of the golf ball). There's rich theory of how to model these; in Electrical Engineering programs, we are taught about this in lectures called "signals and systems", or the like. 

Now, these properties of real-world systems simply mean that the output of your load cell contains less information than the output of your phantom camera. You can't fully reconstruct what you see on that, mathematically – one system is more band-limited than the other.

What you can do, however, is try to correlate any impact with the best estimate for a true impulse response of the system you can get. That's easy to do, but it requires you to estimate the impulse response – but maybe a bit of correlation applied to the load cell signal and a signal modeled from your camera data suffices as an estimator for the impulse response.