Get a clear acrylic tube, about 1.5" diameter. Slowly lower it down over your frog until he jumps up into it. Cap ends with your hands till you get him where you want him. You can cap the first end with a piece of Saran Wrap.
This method works great without stressing your frogs. They will watch your hand but they don't even see the tube coming!
Its amazing how much better the tube works than a small condiment cup. Its like they go into the tube for protection. I use a tube that is a little less than 1" in diameter. I like it better because the frogs have a tough time turning around in it so I don't have to hurry to close the other end. I have even used that size to catch adult leucs.