The Heliopan ND filter which is adjustable from 1 to 6 stops of ND by simply turning the calibrated rim on the filter. The Heliopan Vario ND filter is totally neutral in color, it is mounted in a black anodized brass ring that is calibrated for ease in repeating a desired density.
Reviewed by 2 customers
This is way easier to use than a fixed ND filter. Spin the dial out to the minimum and frame your picture, then spin it in to reach your desired shutter speed. Easy as pie. It's also a useful polarizing filter when dialed out to the lightest setting. I did, on some of my test shots, get alternating light and dark quadrants (Nikon D90 with 35mm f/2 lens) when the filter was dialed in to maximum, That may have been a fluke of lining up the polarisers with the sensor grid. Though backing off from the maximum a millimetre prevented that effect. The filter also doesn't have any threads on the front, so you'll have to pop off the filter before putting your lens cap back on. I found that when the filter was dialed in towards the dark end, I had to use Manual exposure mode and trial-and-error to set the exposure on both my D90 and D7000. In short, though, a very useful and handy filter to have -- and definitely worth the price
This is indeed the best Variable ND Filter available. I purchased this 52mm size at first because I didn't want to spend all the money on a 77mm since I was using mostly 46mm, 49mm, and 52mm filter thread lenses anyway. As time went on I began acquiring lenses that were 55mm, 58mm, and 77mm.. I then purchased the Heliopan 77mm Variable ND Filter. Why? Because this is the BEST one out there! If I would have known from the beginning, I would have spent the money on a 77mm never looked back. It's one of the best investments I've ever made. Camera bodies and lenses come and go...but this filter is forever.