>>4221356Depends on the beach and where the good surf is coming from. My EF 75-300 on my APSC couldnt keep with the distance unless I cropped a lot and even then it lacked detail. I would say get a 400mm or more but it really depends on the location.
Pic related, the best I could do, even though I'm planning to climb a rock near the sand next time. The 75-300 is dirt cheap but it can get the job done.