If you're taking photos (or especially videos) outdoors in sunlight, you NEED a variable ND filter. When shooting video at 30 frames per second, you need to keep the shutter speed at 1/60 (due to the 180 rule) to achieve natural blur and smoothness. If you want a nice, blurry background at f/2.8, chances are your image will be terribly exposed, even at ISO 100. Your only options are to increase the shutter speed (and spoil the natural look by causing annoying "chopping") or increase the shutter speed to f/16, which will flatten your image and remove the desired blurry background! The variable ND filter is included in delivery. When attached like variable sunglasses, it lets in a lot of light, much like an intimidating bouncer at a nightclub. So just turn the ring on the filter and you can get your shot perfect! Two little things threw me off about this particular filter: 1. The ring doesn't have any real stops, just continuous rotation, so you can't really keep track of the specific amount of light you're letting in. 2. When the filter is on my Tamron 28-75 2.8 lens, I cannot put the lens cap on at the same time. Not a problem, but annoying when you want to quickly rotate a photo or video. But given the price, it's hard to argue that this isn't a great buy.