Would you need to show 5 mins of you in a store, if you stole in last 30 seconds? I don't get your logic. That would be 4mins and 30 secs of wasting people time.
The video would need to include the violation of the criminal code you were charged with.
In the specific example that you're asking about, if we're getting pedantic, that would include the moment that you picked up the item(s) that you stole through the time you left the store (or passed the point of purchase in some states) without paying for it. It probably would be a great idea to also show video that had a clear image of your face (typically the camera at the entrance door).
So, in our case here, if you're going to say that entering the building was a crime, and the way a person behaved once inside was a crime, showing video of both seems a reasonable standard.
However, a judge is a king in his court. He gets to decide...until and unless he is overruled by a higher court.