I love fly fishing. I am an International Federation of Fly Fishers Certified Two Hand Casting Instructor with fifty years experience in fly fishing, casting and fly tying to share. Please feel free to send me an e-mail and I will tell you what I know. My areas of knowledge are in fly fishing and fly tying for North Eastern trout, Landlocked salmon and the experience of over thirty five rivers world wide fly casting to Atlantic Salmon.
The start of any, from the dangle, two hand cast is to make sure that all slack is out of the system. Slack that must be eliminated by using part of the lift is a delayed transfer of energy from body to rod to line. Slack in the lift can even become slack at the beginning of the sweep. The first upward movement, or lift, is used to clear line from the surface tension to make our next move easier and afford the ability to make a well placed and properly shaped anchor set. A rule of thumb in tip height to a lift would be to clear half the line from the water. A proper lift will find the entire rod moving upward and not just the tip. A hinge lift is ineffective and will cause added slack.
The shotgun lift is that basic move to get things fluid. Other lifts like crescent, cut and spiral are more dynamic and can be effective in situations that need a bit more energy or a change of position of the line. The shotgun lift is made with a slow, S-L-O-W, short, perpendicular rod movement up with an appropriate slow tempo. Speed is not necessary. There needs to be variation in the power, tempo and height of the lift determined by river condition. A flat mid section of a pool might require less power on the lift that say the faster moving tail out. A key factor about any lift is that there is no abrupt movement. Between lift and sweep there is no pause. We call them using two words but they are one movement. The concept of power on and power off with tempo is always in effect.
The key to any well executed lift is the judgement of power required to make the line free to move upward and transition to the sweep without a stop. This is where power to tempo transforms to the dramatic power at the start of your sweep. Use your lift wisely and concentrate on the ability to get your casting to feel continuous from it's very first movement till you follow through and make the presentation back to the water.