Focal distance:400mmAperture:F8 (Fixed)Lens construction:6 elements in 2 groupsPicture angle:6 degrees 8 minutesLens length:82mmMax. diameter:74mmFilter size:67mmClosest focusing distance:1.15mMax. macro magnification:1:2.5Focus system:Full manualMount:T-mountWeight:340g/ 11.99oz・Extremely compact super tele lens・Full format camera focal distance is 400mm. For APS-C size it is 600mm and for ''micro 3/4'' the focal distance becomes 800mm・A compact optical design combines silver deposition mirrors and pure optical lensesThe Kenko mirror 400 mm F8 super tele lens for Sony Alpha is extremely compact and lightweight. Useful for those who prefer shooting active scenes and have some sub super telephoto lens along with primer lenses. When shooting birds animals or flora the Kenko mirror 400 mm is ideal.