Overviews: Aputure Macro Tube Set includes 3 tubes of different lengths: 13mm, 21mm and 31mm. Use them individually or in combinations, for 7 different possibilities. Main features include built-in electric pins for great TTL and AF, solid metal construction, elegant design, sturdy & durable, and compatibility with a wide range of lenses. Auto Extension Tube Distance Reading of Master Lens Image Magnification Ratio Field Coverage(cm) Distance From Lens Front to Subject (cm) Exposure Factor 13mm lnf. 0.5m 0.24 0.35 10x15 6.9x10.3 21 16 1.5 1.8 21mm lnf. 0.5m 0.40 0.51 6x9 4.7x7.0 13 14 2.0 2.3 31mm lnf. 0.5m 0.72 0.83 3.3x5.0 2.9x4.4 7.7 7.0 3.0 3.4 13 21mm lnf. 0.5m 0.64 0.75 3.8x5.6 3.2x4.8 8.5 7.5 2.7 3.1 13 31mm lnf. 0.5m 0.96 1.07 2.5x3.7 2.3x3.4 6.0 5.5 3.9 4.3 21 31mm lnf. 0.5m 1.12 1.23 2.2x3.3 2x3 5.3 4.9 4.5 5.0 13 21 31mm lnf. 0.5m 1.34 1.47 1.8x2.7 1.6x2.4 4.5 4.2 5.6 6.1 Features: 1. Perfect for macro shooting 2. Supports accurate TTL & Autofocus 3. Compatible with all EF and EF-S Canon lenses 4. Strong, sturdy, durable 5. Elegant design 6. Light & portable Package Includes: 1 X Aputure AC-MC
