NOTE: This is a FULL Manual Lens, NO Electronic Contacts, your camera will not detect the lens when mounted, that's why it shows "LENS NOT ATTACHED", please switch to MF MODE in order to use this lens correctly. Tips to use our Manual Lens: 1) Set the mode dial to Manual (M). 2) Set the Release w/o Lens option in the camera menu to Enable. 3) Set the Shutter lock option in the camera menu to Off: no lens. | Fine tune the front focusing ring to make subject in-focus and take a sample picture. If the picture turns out dark, take the following steps to improve, 1. Lower the shutter speed, from 1/500s down to 1/100s or slower 1/50 etc; 2. Raise the ISO Number, from ISO 100 to ISO 200/400/800 etc; 3. Use a remote shutter release and tripod to increase image stability; 4. Switch position to allow more environmental light coming through the lens into the camera imaging sensor. | Multi coated low-dispersion glass, anti-reflection coating, manual focus telephoto zoom lens to use with DSLR SLR cameras. | ADVANCED OPTICS / SUPER ZOOM / SOLID FULL METAL CONSTRUCTION / MANUAL FOCUSING | 420-800mm f/8.3-16 Manual Telephoto Zoom Lens for Nikon D850, D810, D800, D750, D700, D610, D300, D3100, D3200, D3300, D3400, D5100, D5200, D5300, D5500, D5600, D7000, D7100, D7200, D7500, D50, D60, D90, Df, D3, D3X etc.