Is there a black circle when Canon C70 uses 0.7 1 to switch to Sigma 18-35 full focal length?

It is estimated that the lens of Sigma 18-35 can be used above 24 mm, and the lens seems to be designed according to aps-h sensor specifications (it can be used with Sigma SDQH fuselage), so its image field size can't cover Quan Huafu. According to the actual measurement, there is an obvious black circle at the wide-angle end. With the increase of focal length, the black circle becomes dark, so it is not obvious above 24 mm The C70 is the camera of S35. With the addition of the defocused brightness enhancement adapter ring, the image field coverage of Sigma 18-35 can also refer to the above.