Towards the end of last year I was made aware of this Variable ND filter from 7 day shop which offers a variable ND filter range of between 2-8 stops. The price for this at the time was £33 for a 77mm fit filter. Much cheaper than other options I had seen such as the Big Stopper. Although that filter does do 10 Stops.
The advantage of a ND filter that goes to a high stop number is that you can use it creatively for a number of effects. These effects include ‘motion blur’ – often used to blur moving water, clouds and moving objects.
Not having a large stopping filter I decided to purchase the filter to add to my kit bag. The filter itself is round and screws onto the end of the lens. Turning the filter adjusts the amount of stops the filter has, letting less light through as you increase the stoppage. The filter being of the screw in type will only fit lens of that filter size. A slight disadvanage to the filter is that if you want to add a square type of filter set onto the filter you would need a different sized filter adapter as the filter thread on the end of the filter is slightly larger that the thread size the filter has.
I have tried this out recently and have found it useful to blur water movement on cloudy days – even during the middle of the day – a delay of a few seconds is enough to get a nice blur. Forcing the filter to move past its stop limits produces some vignetting, but this is outside of the range.
Below are a couple of recent shots taken using the filter. They both are post processed using Topaz Black & White Effects.
Longstock – Taken on Canon 50D with 17-40 USM L Lens. ISO 100 F16 2.5 Seconds with 7 Stop ND Fader Filter. Edited in Topaz Black & White Effects.
Old Swanage Pier – B&W. Taken on Canon 50D with Canon 17-40mm L Lens. F20 13 Seconds ISO 100. Fader ND Filter used. Converted into black & white using Topaz Black & White Effects
[box type=”info”] Pros The filter works within its range well, and is very nicely priced compared to other big stop filters. [/box]
[box type=”warning”] Cons The filter thread is wider on the outer edge of filter. Vignettes beyond the manufacturers recommend range of stop (Fine up to 8)[/box]