God means different things to different people, so deciding whether or not such-and-such a person believes in God can be tricky because you don't know which God they mean.
In as much as I really care about what Einstein said about God, I certainly know that he rejected the idea of any religious God. If he saw the harmony in the Universe as the sign of a creator, then sure, fair enough, but it doesn't particularly sway me. Newton, too, believed in God (and spent almost as much time studying Revelation as he did gravity), but so what? Up until around the middle of the 19th Century, science and religion often walked hand-in-hand, because once the attitude of the Middle Ages was shaken off it was clear that neither necessarily had much to say about the other. Scientific study can be as well-motivated by a desire to understand the wonders of Creation as it is by just an idle curiosity.
Also there's a cultural aspect too. As and when religion and notions of God disappear, and then independently re-emerge because of scientific studies leaving room for no other conclusion, then you'll be able to persuade me that God exists in the minds of scientists because he *has* to, not merely because they think he does.