Review on Tiffen 77VND 77mm Variable Neutral Density Filter: Perfect for Camera Lenses, Black by Lawrence George

Versatile but eventually returned to try square filters instead. Pros: You can focus by setting it to a lower aperture setting and then cranking it. If you have used fixed aperture filters you cannot do this, you must remove the filters as it is difficult for the camera to focus with too many filters. Difficult to use in conjunction with special circular polarization (because two polarized lenses are used, facing each other to create variability). Tips: Use the focus back button! Set the filter to minimum and then focus on the scene (you can set the camera to use a separate button to focus instead of the shutter button). Then set the filter to the desired aperture, now set the exposure. My camera seemed to do a good job of auto metering with lots of filters (just no autofocus). Now take your shot! (from a tripod with a remote trigger or of course with a delay timer).