I've been looking around and can not find an answer just trying to do some math for focal lengths etc.... anyway can anyone help out with the sensor size on the 4mp hik cameras specifically the 2cd3345 and the 2cd3145
Yea, the 3MP and 4MP are 1/3". The 4MP is physically bigger than the 3MP.
They both use 2.2 micron pixels.
The 3MP uses a 3.5MP sensor, but you can't get all the pixels on an output. All outputs discard pixels (either 2048x1536 or 2304x1296 scaled to HD -> 1080 or 720)