I currently live in suburbia and there's a large field behind my house. Since yesterday I've noticed 3-4 deer grazing there. I've approached them three times at varying times of day and haven't been able to get closer than 15-20 feet. The only zoom lens I have is Sony's E 55-210mm F4.5-6.3 OSS. I haven't yet successfully used it to reach my goal of a sharp picture with a deer as the subject. This is the closest I've gotten with f/8, iso 100, and 1/125":
(raw file: https://drive.google.com/open?id=0B7ZsyhVjBC94QTM2R0FfeS1rRk0) I'd rather the deer be a bit larger in the frame. Also, because I had to zoom in all the way to get the deer to appear this close, it turned out low-resolution.
An article I found elsewhere recommends picking at the stuff they're grazing on to make them more comfortable, but when I tried this I found that it either scares them or doesn't seem to do much of anything. Equally unuseful (and probably peculiar to onlookers) is squat-walking toward them in a broad zigzag pattern. Could it just be that I'm not patient enough? I've spent what felt like ten minutes slowly inching up to them, and they still either naturally wander off or hop and run away whenever I get within about 20 feet.
My neighbor's allegedly been able to see them drinking out of his bird feeder from inside his house. They've likewise seemed pretty calm when I've peered at them from behind my fence, but the most recent time I climbed over it to get closer they grew scared and bolted. Simply investing in a better lens isn't an option; I need to know how to get closer.