That’s the problem then. Most cameras need 6v and rechargeable ones are only 1.2v (as opposed to 1.5v for normal ones). So 4 rechargeable batteries only make 4.8v. Not enough for the camera to work properly.
If you’re getting another one and hoping to use rechargeable batteries, I would try to get one with the facility for at least 8 batteries. Even some of the cheaper ones have room for 8.