Tele Vue digital camera adapters allow solid, accurate attachment of digital cameras to appropriate Tele Vue eyepieces for "afocal" imaging. "Afocal" means collimated light between the telescope eyepiece and camera lens. To minimize vignetting and maximize image quality, we suggest using the following Tele Vue eyepieces, as their long eye relief best matches the internal pupil of the camera lens; 40mm, 32mm Plossls, 35mm, 27mm Panoptics, 22mm, 17mm, and 12mm Nagler type 4, 31mm Nagler type 5 and all Radian focal lengths. Radian eyepieces require the adapter included with DRA-XXXX models. Overall, we found the 35mm Panoptic achieves the least vignetting in afocal applications.
One more thing to note is that because camera pupils move with zooming, you may find minimum vignetting at the extremes of zoom positions. Results will vary depending on the camera used. Not shown in above photo, all adapters include 3 small thumb screws for easy use without tools.