Canon EF 17-40mm f/4L USM EF17-40mm F4L USM Instruction Manual - Page 9

8. Filter Holder 9. Extension Tubes (Sold separately) You can attach Extension Tube EF12 II or EF25 II for magnified shots. The shooting distance and magnification are shown below. There is a gelatin filter holder at the rear of the lens. Cut the gelatin filter to fit within the white frames. Then insert the gelatin filter into the filter holder. • Only one filter can be used. • When you use a gelatin filter, ghosting may appear in the image. EF12 II EF25 II 17mm 40mm 17mm 40mm Camera-to-Subject Distance (mm) Magnification Near Far Near Far 155 159 0.83× 0.70× 206 271 0.59× 0.32× Incompatible 196 218 1.02× 0.70× Manual focusing is recommended for accurate focusing. ENG-8