>>4131350M43 is great for superzoom. If you're fine with being basically stopped way the fuck down with the ISO cranked. No one makes a f11-f13 200-800mm zoom for full frame, but if they did it would still be bigger than this 100-400 f5-f6.3. Canon filed a patent for one and I expect it to be as big as the sigma 300-800 at least.