Our dog will chase off anything. But, she's a browser, so she needs to be kept out of the berry garden! (she's not deprived! when in season we will be out on the property and she'll get to browse on plums, cherries, blackberries and huckleberries)
TWO fences. A bit of a maintenance headache (having to trim/maintain between the fences). Maybe get by with a 4' outer and then a 6' inner. Deer wouldn't be able to launch over the inside taller fence. Depth perception thing: most probably wouldn't even attempt the jump. I'd read about this a long time ago when reading up on fencing strategies for various things: also read up on what various airports do to try and keep critters away (mainly birds*). This double-fencing strategy was mentioned as being effective. BEST was said to be humans walking around; then dogs.
* Our berry garden has a 6' high fence (local deer just haven't attempted to scale it). To discourage birds we run wires overhead with streamers hanging off them; this seems to work pretty good. Speaking of birds, interestingly enough we never had crows ravage anything of ours (neighbors have been hit); I am always friendly to crows (they follow when I mow); crows also chase off the big aerial threats (hawks and eagles), so they help protect our fowl.