The straighter the face of the club, the more difficult it is to play. Even though this is true, it is not true to the extent most people think. In more specific language, what I'm trying to get across is this: granted that it is easier for the average golfer to hit a good shot with his eight-iron than it is with his four-iron, he will obtain much better results than he usually does with the middle irons if he goes about playing them right.
You can play the short irons with a restricted swing and just hit down on the ball, and sometimes get away with it. That won't work with the middle irons—the lowest point of the arc of the swing is not so far in advance of the ball as on the shorter irons. You must execute a golf swing. On the middle irons you don't have to hit the ball with a lot of force to get it out the distance you want. The club will do it for you if you perform a reasonably good swing. The backswing should be almost as full as the backswing on the long irons and the woods. This necessarily means taking a good unrestricted body turn.
As compared with the short irons, the longer turn you make in playing the middle irons provides more clubhead speed for you. There's more acceleration of the hands through the ball. There's no need to try to speed up your tempo. As a matter of fact, a golfer is wise if he tries to keep the same tempo on all his shots and realizes that he derives his distance not from speeding up his swing but from the built-in acceleration that the longer turn generates.
from DOW FINSTERWALD Tequesta Country Club, Tequesta, Fla.