If that is what you want, then you need to investigate Circular Fisheye Lenses which are made for APS-C Cameras.
As I already mentioned, the Samyang 8mm Fisheye Lens you are asking about will not give you that type of image.
A Fisheye Lens which will give you that Circular Image is the:
Sigma 4.5mm F2.8 EX DC HSM Circular Fisheye
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