Description: 1. This adapter helps you mount your M42 lens onto a camera with EMF AF confirmation. 2. Allows focusing to infinity. 3. Supports AV (aperture priority) and manual mode. 4. The chip enables the camera's viewfinder for focus confirmation light and confirmation sound. 5. EXIF is fixed F1.1 to F64 / 1mm to 65535mm . For Setting Program: 1. Set the maximum aperture of the lens. 2. Set the desired aperture on the camera. 3. Focus and measure the object, when focus is achieved. 4. Set the lens aperture to the same desired aperture as the camera setting. 5. Press the shutter button and take the picture. The ring has 3 setting modes: Mode 0 - enter the lens's maximum aperture. Mode 1 - enter the lens's length. Mode 2 - enter the lens's focus Mini adjustment. Turn the aperture dial to a specific aperture value and press the shutter button to enter a desired setting mode. For example, if you want to enter the lens's maximum aperture, turn the aperture dial to F/2.0 [which means number 0 to the ring] and press the shutter button. You are setting the ring in the maximum aperture input mode. : 1. Do not touch the golden contact points of the circuit board of the emf chip when attaching and removing the ring from your lens and camera. 2. Do not use F/64 shutter + F/57 shutter + F/64 - shutter combination during normal shooting. This combination sets the emf chip in setting mode. If you accidentally enter this mode, select an aperture value between F/6.3 and F/51 and press the shutter button once to exit. Compatible with: All M42 lenses for 5D Mark III, 5D Mark II, 5D, 7D, 70D, 60D, 50D, 40D, 30D, 100D, 700D, 650D, 600D, 550D, 500D, 450D, 400D, 350D, 300D, 1100D, 1000D. Does not work with for 30, 30V & 33V and 1D series. Material: Metal Color: Black Package Contents: 1 x Lens Adapter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture to be slightly different from the real one. The allowed measurement error is +/- 1-3 cm.