The way this place is layed out, where I can get real close to the nests, if I still had my 400L, I could get all the swallow in-flights I wanted. They fly within a foot of my face when returning back to the nests. but, the Bigma just doesn't focus fast enough and weighs twice as much as the 400L. Still, I might give it a try the next time I go out there. 

