The world of long exposures is one hidden to the human eye, a world that can reveal amazing visual scenes when the movement of dynamic elements are smeared across an image captured on film/sensor. The images below explain it all.

Captured with Lee Big Stopper

Captured with Lee Big Stopper

Due to the minimum light sensitivity of cameras, we can only capture long exposures in natural light when the sun isn’t out. That’s why there are super strong ND filters like the Lee big stopper, Hoya ND400, Singh-Ray Vari-ND, B+W 110 and others. These are simply very dark glass filters, designed to allow only a fraction of the available light through, allowing the photographer to take much longer exposures in bright light. The main challenge in the design of these filters is to make them color neutral. It’s very hard to dye the glass so dark without affecting it’s color balance.

Solid ND filters come in many strengths and in both screw-in form and the square format designed for filter holder systems like those of Lee and Cokin graduated filters. Some companies make everything from 0.3(1-stop) to 1.5(5-stop) solid ND filters, but the most common one is the 10-stop (the filters vary from 9-11 stops). These filters can be combined to get ridiculous exposure times, because the exposure time increases exponentially with each stop of ND filter. An exposure of 1 second becomes 16 minutes with a 10 stop ND filter, add another 10 stop filter and you’re exposure becomes almost a day long. If you can find a constant light source, it is theoretically possible. If you want to know more about ND filters, the internet is full of information so just google and I’ll get to my review.

To avoid confusion I will use the following two terms appropriately throughout the article

1. Vignetting – When the edge of your filter holder appears in the image when using a wide angle lens
2. Light fall off – When the edges of the image is slightly darker than the center (common occurrence when shooting with wide lenses at their maximum aperture)

Singh-Ray Vari-ND

I have no experience with this filter, but it is far more expensive than it’s competitors, only availably directly from SR and I’ve seen some nasty ghosting problems caused by it from another photographer.

B+W ND110

I’ve had one of these and the color cast was horrific. It rendered all warm colors with a magenta cast that was impossible to correct in post processing. Unless you’re doing black and white photography, I wouldn’t recommend this filter.

Hoya ND400

Some of my favorite photographers use the Hoya ND400 and have gotten brilliant results with it. The only downside of it is that it’s a screw in filter, because you have to screw the ND filter in, then the adapter ring into the ND filter which results in the holder sitting further forward and the chances of the holder’s edges appearing in the image is very good in most wide angle lenses. Andy Mumford, the photographer of the two masterpieces below did something quite ingenious. He removed the glass from the screw-in ring and fixed it inside a Lee wide angle adapter ring, thus getting rid of all vignetting problems. Practically simple, but something tricky to do with an expensive piece of glass!

Palafitico by Andy Mumford

Captured with Hoya NDx400

Purple by Andy Mumford

Captured with Hoya NDx400

The Blanket by Philip Perold

Captured with Hoya NDx400

Here are two unprocessed images, one taken with the ND400 and one taken without it. The only  RAW adjustments was to set the white balance of the ND400 image identical to that of the one without it. Images are courtesy of Philip Perold

Lee Big Stopper

I bought a Lee big stopper about 2 months ago and I have now shot enough landscapes and waterscapes to do simple a comparative review. I won’t go into detail, but rather just provide a short list of it’s aspects and enough images for you to draw your own conclusion.

• I have owned a B+W ND110 and Hoya  ND400 prior to the big stopper and so far I like the Big Stopper the most, by far.
• I don’t think it is optically superior to the ND400, but the fact that it’s a square filter is very convenient. There are always vignetting issues with screw in filters as mentioned above.
• It does have a cast, but it is blue, which is much easier to correct in post processing than magenta.
• It has a seal ring at the back that prevents any potential light from leaking into the filter holder.
• The images below clearly show light fall off, a blue cast and that the filter robs the image of some contrast, which are the downsides of using this filter.

The blue cast is quite evident, but it is easily removed in the RAW processing stages. Having used the nd400 and ND110 and seeing how the Vari-ND performs, I would highly recommend this filter of as the best one!