1. Canon EF 25 II Extension Tube for EOS Digital Cameras. Buy On Amazon. 2. Kenko Auto Extension Tube Set DG 12mm, 20mm, and 36mm Tubes for Canon EOS AF Mount. Buy On Amazon. 3. Kenko Auto Extension Tube Set DG for Canon EOS Lenses A-EXTUBEDG-C. Buy On Amazon. How to calculate the magnification of an extension tube. An extension tube increases lens magnification by an amount equal to the extension distance divided by the lens focal length. For example, let us consider the Canon EF 50mm f/1.4 USM, which has the following specs: Maximum Magnification 15X; Minimum Focus Distance 450 mm Extension tubes of 7mm, 14mm, and 28mm lengths can be used individually or in any combination of the three for greater magnification. Lightweight design with metal mounts for durability and longevity. Fits Canon EOS DSLR cameras and all EF/EF-S-mount lenses. Extension tubes are better suited for f=50-60mm lenses. It's not just the length of the 100 mm macro which makes the 25 mm tube ineffective - it has an effect, yes, but it's not the main factor. It's because the magnification is already very high at 1.0x, and the 25 mm tube adds 0.25x making only 25% more. For Canon EF Lenses and Cameras. 12mm, 20mm, and 36mm Extension Tubes. Shortens Minimum Focus Distance of Lens. Autofocus & Auto-Exposure Functionality. Aluminium Mounts, Gold-Plated Contacts. In stock Ships tomorrow. You Pay: $61.95. Add to cart. (1) review. PvkX.

canon ef 25 extension tube