近摄接圈也叫近摄接环。原理是透镜成像公式。在焦距不变的情况下,像距大了,物距减小,拍摄物体就近了。近摄接圈的具体用法是将其安装于镜头和机身之间,由于它是直通无镜片的,所以不影响光学品质,成像优于近摄镜。但影响进光量,需增加曝光。目前近摄接圈有无触点和有触点两种,有触点的近摄接圈用时就像用镜头一样装到机身上,接圈的前面再装上镜头,对相机正常的测光、对焦没有任何影响。通常是金属结构,做工质量很好,坚固耐用。而没有触点的近摄接圈则无 Close loop is also known as close-up ring. The principle is the lens imaging formula. In the case of the same focal length, like the distance from the object distance decreases, the subject is the nearest. Close loop specific use is to install it between the lens and the fuselage, because it is straight through the lens, it does not affect the optical quality, imaging better than the close-up lens. But affect the amount of light, need to increase exposure. At present, there are two kinds of contact lens contactless contacts and there are two contact lens proximity ring with the lens as the same as the body mounted on the camera, then ring in front of the camera, the normal camera measurements Light, focus has no effect. Usually a metal structure, workmanship is good, durable. There is no contact near the camera ring