This lens is an ultra-wide "FISHEYE CIRCULAR" photographic lens compatible with Canon EOS series cameras. While it doesn't require an automatic instant-return diaphragm control mechanism, adding a diaphragm control device can significantly improve photo quality. The multi-coating helps reduce reflections for clearer images. Photos taken with this Peleng 8mm fisheye lens produce a circular image with a 24mm diameter, meaning it doesn’t fully cover a 24x36 frame. There will be some empty space along the long edges and dark corners around the circle. The center of the image aligns with the center of the frame.