Need help in chosing Lense

This is full frame isn't it? If it is then something around 85mm - 100mm would be the classic portrait lens. For smaller APS-C sensors then the 50mm lens is a close equivalent.

the carl zeiss 85 mm for sony is outstanding, I owned it and learned to use it...bokeh is amazing, just a really nice lens, however pricey...but, u get what you pay for sometimes. i also used it on the a900

I agree with thadonnie.