I don't think he was shouting at Jake, he sounded like he was shouting at the paps, he was saying "you could have had a better shot if you'd backed up" the very first thing he says to jake is something like "let's make this a good shot" and Jake laughs and gets out his wallet
Looks to me like Jake was going to give him money, saw the papparazzi and was like "shit, I want out of here" then the begger started yelling and he went back