Forgetting Depth Of Field When Using Fisheye

I use a 15mm fisheye lens for when I want to either take in really wide landscapes and later defish and when I want to stitch together a bunch of photos, usually to make a 360 panorama. I keep stopping down to f/8, f/11 or more because I don't want to have a depth of field that is too shallow. But I keep forgetting that the depth of field isn't what I'm used to it being on my 50mm lens. I've also been focusing too far out, since I usually leave it on manual focus (near infinity). What I should be doing, thanks to Depth of Field Calculator, is focusing at, let me hazard a guess, 7 feet with an aperture of f/4 and everything from roughly three and a half feet (which is less than the height the camera is off the ground, so everything should be in focus on the near end) to infinity will be in focus. Not only that, but I'll have a much quicker shutter speed so moving objects won't be as much of a problem. (The site ever so neatly indicates that the hyperfocal distance is 6.2 feet, so my guess wasn't far off.)

I am used to 50mm land, where f/4 at 7 feet will leave everything from 6.3 to 7.8 feet in focus, which is far too shallow a depth of field for landscapes and or 260 panoramas.