The M42 close-up adapter can be used for remakes. It is divided into three adapters. The adapter is placed between the SLR body and the lens, and can be combined arbitrarily to obtain the required magnification The conversion is: magnification = the length of the adapter / the focal length of the lens. According to this, multiple adapter rings can also be combined to match different lenses to achieve the required close-up effect The close-up of the M42 mount can turn an ordinary lens into a lens The three sections are 7mm, 14mm, and 28mm, respectively, and can achieve 1:1 magnification with a 50mm header There are three sections in total, which can be used alone or together, but the cannot be linked