• 34mm fully illuminated field but can handle full frame as well
• 95mm back-focus (55mm when back focus spacer and M48 ring installed)
• Drops f/ratio from native f/7 (840mm) to f/5.4 (647mm)
• Reduces exposure time by 68% compared to native f/7
• Built-in 2" filter cell for mounting filters
• 3.18 x 2.12-degree field of view when used with a full frame camera
• 2.08 x 1.39-degree field of view when used with APS-C crop sensor

• The EdgeHD .7x Focal Reducer Lens makes your EdgeHD 1400 one full F-Stop faster than f/11, reducing your exposure time by half to capture the same brightness of object
• 5-element lens design
• Maintains similar flat-field performance as native EdgeHD optical design
• Increases field of view by 43% to better capture wide field images
• Threads directly onto the 3.25" threads of the EdgeHD which reduces mechanical vignetting and allows for use with larger (full frame) sensors and Off-Axis Guiders
• Maintains the identical back focus when used at f/11 and provides generous back focus to accommodate additional accessories and wide variety of cameras
• Allows use of existing EdgeHD T-Adapters with or without the Reducer Lens

• The EdgeHD .7x Focal Reducer Lens makes your EdgeHD 800 one full f-stop faster than f/10, doubling the equivalent exposure at f/10
• 4-element lens design
• Maintains similar flat-field performance as native EdgeHD optical design
• Increases field of view by 43% (double by area) to better capture wide field images
• Optimized for APS-C sized sensors, including most DSLR cameras and Nightscape CCD cameras
• Provides generous 105mm back focus to accomodate additional accessories and a wide variety of cameras
• Compatible with EdgeHD 800 T-Adapter

• The EdgeHD .7x Focal Reducer Lens makes your EdgeHD 9.25" one full F-Stop faster than f/10, reducing your exposure time by half to capture the same brightness of object
• 4-element lens design
• Maintains similar flat-field performance as native EdgeHD optical design
• Increases field of view by 43% to better capture wide field images
• Threads directly onto the 3.25" threads of the EdgeHD which reduces mechanical vignetting and allows for use with larger (full frame) sensors and Off-Axis Guiders
• Maintains the identical back focus when used at f/10 and provides generous back focus to accommodate additional accessories and wide variety of cameras
• Allows use of existing EdgeHD T-Adapters with or without the Reducer Lens

William Optics FLAT6AIII Adjustable Field Flattener

2" x0.8 reducer APO adjustable field flattener, It has M63 threads for GT71 /GT81 /Z103 /Z81

• Refine your flat-field performance.
• Fully multi-coated Ohara glass optics.
• Reducing factor: 0.8X.