The ideal lens cap! The JJC White Balance Lenscap is a lens cap that you can use immediately for a neutral white balance measurement. How does it work?
You set your camera to make your own white balance setting. You follow the actions to be performed, with one difference: you do not focus your camera on a sheet of white paper, but you stand with your back to your subject and focus on the camera with lens cap in the direction where you will be photographing. ... Being able to play. The white ball on the JJC Lensdop absorbs the light that the subject is shining and so you have a completely neutral white balance.