A slight shadowing in the corners is a normal optical effect that can occur when using the 0.5x ultra-wide lens, if the ring on the Ring Stand Case is fully closed.
To get a completely clear shot, simply open the ring stand before you take a photo.
We hope this tip helps you get the perfect photos!
We truly appreciate your support and understanding. If you have any other questions, please contact our customer support here and we will be happy to assist you.