Chargers for NiMh AA batteries

I am new to this forum and also to digital camera techniques. I would like to know: Is there different types of chargers for NiCad or NiMh batteries. I am using Sanyo and Sony NiMh rechargeable batteries, and only have a Vanson Nicad AA battery charger. On the charger, it states to charge 2 AA battery for 6 hrs, or 4 AA battery for 7 hours. After charge, I can only manage about 2 hrs operation on my camera, which uses 4X AA batteries. Please help me, as if a different charger is required, I then will get one soon. Thanks.

If the charger is stated only for NiCad and mentions nothing about NiMH on it, I wouldn't use it to charge those batteries. Nicad and Nimh are different internally and needs an appropriate charger. On my Sanyo charger, there is a switch on the back to switch between charging nicad or nimh.

The charging characteristic for Nicad is very different than for NiMH. A charger which has a switch, for choice of battery type, will alter the charging pattern to suit the battery type.