We don't recommended to combine 2 or 3 rings at same time if the focal length is less than 70mm.the auto focus is easy when mount ONE ring , but difficult for 2 or 3 . we suggest to set your camera in MF . Combined with 3 tubes in different length: 12mm, 20mm, 36mm, can be used in any combination or individually to obtain the different magnification. With camera of TTL,AE(through-the-lens, automatic exposure)type it gives perfect coupling except when combined with electronic flash AE unit. With camera of TTL,AE(through-the-lens, automatic exposure)type it gives perfect coupling except when combined with electronic flash AE unit. Auto Focus extension tube, designed for for Canon EF/EF-S 35mm lens to shoot at closer distance with higher magnification. It can instead of expensive Close-up lens, with it , I'm sure you don't want to buy another Close-up lens.

Maximum Focal Length: 36 Millimeters. Camera Lens Description: 35 millimetres. Compatible Mountings: Canon EF. Lens Type: Macro. Brand: VILTROX. Country of Origin: China. Manufacturer: JYC Technology. Date First Available: April 9, 2016. Is Discontinued By Manufacturer: No. Best Sellers Rank: #64 in Lens Extension Tubes. Customer Reviews: 3.9 out of 5 stars 159 ratings 3.9 out of 5 stars. Item model number: DG-C. : B01E0W26RS. Item Weight: 5.4 ounces. Product Dimensions: 2.36 x 2.36 x 2.68 inches.