Canon 5d2 camera, lens 70-200 lens, taking portraits at home, why are there dark corners in the left and right corners? Still obvious? Ask! thank you

If external obstacles are removed, it is necessary to check whether a protective cover is installed. Is it the original hood?

Is a similar UV mirror too thick? Take it off and look at it directly with the lens.

It is normal for a lens to have some dark corners in the four corners. According to the quality of the lens, the obvious degree of dark angle is different. But there are four corners.

Did you show up with your flash? That's because the flash angle is too low and it hits the front of the camera. This has nothing to do with the aperture size.

I usually try to take photos indoors with high sensitivity, such as setting to ISO 1600 or 3200 or even 6400. Use external flash only when it is really impossible. When taking portraits, the external flash will also hit the sky, fill the light with the reflected light hitting the ceiling, and enhance the brightness of the face with a reflector.

Invincible rabbit's built-in flash sometimes really gets in the way and interferes with normal thinking. Generally used for outdoor photography, such as backlighting.