[Ikhanton Amon]

Quote – if I shoot a subject which is well exposed (1-2 stops down)

How do you decide that it is 1-2 stops down and not 2-3 or 3-4 stops down?
The images have a wrong white balance, which affects the way the noise looks. When shooting, it’s better to use as a simple tone curve in the camera as possible. The look of the image is established in post-processing, not during the shot. ISO 100 for Canon 5D2 is not the lowest noise setting, due to the design of the camera. Try ISO 200.
You can check your exposure by shooting the setup in RAW and looking at it in FastRawViewer. Incidentally, this will also let you make sure that your white balance is also correct.
When you say “good exposure on the subject”, what the numbers tell me when I use an eyedropper in Photoshop is 2 stops underexposure. Technically, we mean different things when we talk about the quality image straight out of the camera, and the quality final image. A quality image straight from the camera only ensures that you can edit it to produce a quality final image. You need to determine what a quality image is for the final look. If you are shooting film, can the resulting negative be considered a good quality image? Yes, of course you can consider it a good quality image if you can print a good positive from it, but by the sheer look of the image on the negative film, you would say that the look of it is good, if your criteria is to be close to the final image as possible.
The closer the camera is to high-end, the greater the difference between the camera output and the final look of the video.