This lens accessory TV and also the wide angle were initially designed for older generation camcorders with tiny image sensors. Used on cameras with APS-C sensor, the image circle produced by these lens adapters is too small to cover the surface of the sensor, where vignetting and blur the edges of the image. But this incompatibility is beneficial to creative and sometimes artistic photo, with a little imagination and according to optics used. Especially as these accessories, modernized, are offered at a very reasonable price compared to what was offered before and manufacture "plastic" most of the time, including lentils ...