CAMEA is a novel instrument concept, thus the performance has not been explored. Furthermore it is a complex instrument using many analyser arrays in a wide angular range. The performance of the instrument has been studied by use of three approaches: McStas simulations, analytical calculations, and prototyping. Due to the complexity of the instrument all of the previously mentioned methods can have faults misleading us during the instrument development. We use Monte Carlo and analytical modeling to calculate and optimize the instrument, while the measurements on the prototype validate the model calculations. The prototype gives informations about the background and during the real inelastic measurements reveals the problems arising in the data treatment. The main goal of the analytical calculation is to reveal the effects of the differrent instrument parameters on the resolution and on the intensity of the instrument.