Please note there are two way to install the compartments:
Make sure the flower/tulip lens hood is correctly positioned: the correct orientation is with the larger peaks at the top and bottom and the smaller peaks at the side
It is a normal issue that when you shoot at angle of view 18mm, the vignette will be appeared on the picture.as the flower/tulip lens hood is not designed for one special lens, then could not guarantee
that all the lens will not have the vignette issue,as long as the flower lens hood size=your lens size, then could be used. this issue could be improved just by slightly retun the lens hood and there you go been getting eliminated.
All the K&F concept lens cap is screw-on cap, but the outer frame of lens hood features with no thread, so once attach them together, will be easily fall off, we suggest to attach the lens cap directly to
lens instead of lens hood.