I am wanting to get more serious about wildlife photography. Really want a Canon 500 or 600mm L lens. But I have no first born I can sell,,,,,LOL Just kidding. But they are currently out of my range. So I got to looking at the Sigma 150-500mm f5-6.3 APO DG OS HSM for Canon and was wondering if ti was a good lens. Would that be a good option or stick with the 400 L I have now and put on a convertor and get a 5D mak ll? They will be used on a 7D
Thanks in advance for the help





