What Exactly Is a Big Stopper?
Big Stopper may not be a name that you are familiar with. It is in fact a trade name from Lee Filters to denote a neutral density filter that cuts out 10 stops of light. However it it has also become the generic name for an extremely dense neutral density filter. These filters have become extremely popular in recent years with landscape and cityscape photographers, creating interesting, ethereal looking images. Today we are going to take a look at which filter to buy, how to shoot with it and what you can achieve.
What Are My Neutral Density Options?
There are a number of well know companies that now manufacture ultra neutral density filters. The two main options are screw in filters and square filters. An interesting variation of the screw in filter is the variable density filter. This is basically two polarising filters sandwiched together. As you rotate the from element, you gradually increase the density of the filter down to a maximum of around 8 stops.
The most common version of the filer is the square system. Companies like Lee and Cokin manufacture both 10 stop and 6 stop neutral density filters. The advantage of the square system is it negates the need for multiple filters for different lens sizes. A more recent addition is the magnetic filter. These are regular circular filters that attach magnetically to a lens adapter.
Why Use A Big Stopper?
The idea of a neutral density filter is to reduce the exposure. Usually, this is because the photographer wants to reduce the shutter speed to introduce motion blur into an image. Big Stopper filters reduce the shutter speeds dramatically and so require some special considerations when shooting.
Firstly you are going to need a tripod. It will not only be impossible to handhold the camera at the shutter speeds the filter will give you but also it will make it easier for you to both compose the image and work out your exposure time.
Long Exposure Considerations
With a ten stop filter even in bright light, your shutter speed will be very slow. In low light we could be looking at exposure times in the minutes. For this reason you are going to need a camera remote control.
Most cameras allow you to shoot bulb, that is leaving the shutter open for a period of time that you determine. However for better accuracy a remote control will allow you to set finely controlled long exposure times. The added bonus of the remote is that you will not need to make any contact with the camera. This will help eliminate any slight blur caused camera shake.
If you are shooting with a DSLR you can further eliminate any potential camera shake by switching on mirror lock up. This is usually found in the menu system. Mirrorless cameras do not require this feature. If you do not have a remote control, you can use your camera's self timer to eliminate contact with the shutter.
Measuring Exposure
Measuring exposure with a Big Stopper is a little different than you may expect. Once you have your shot set up and composed, measure the correct exposure without the filter. You are then going to add 10 stops to the exposure. With the shutter speed running into tens of seconds this may not be easy. To help in this, there are a number of useful long exposure calculator apps as well as website where you can download and print a table of exposures. Not all ND filters will cut out the same amount of light, especially in the case of the extreme NDs. Use the tables or apps as a guide and if your filter is slightly under or over exposing, adjust accordingly.
Another issue with such long exposure times is color casts. Big Stopper filters often create a blue cast in the image. To help reduce this, shoot RAW files, these will give you more control over potential color casts in post production.
So what can you shoot with the Big Stoppers. The most common type of shot is one that involves water. This might me waves washing up on a coastline, or the powerful streams of water in a waterfall. The ultra long exposure times given by these filters, creates an ethereal, ghostlike effect in the water and has become a common theme in landscape photography.
Another area where ultra NDs can create interesting effects is in skies. In a similar manner to water, any clouds moving across the sky will become a blurred mass whilst the rest of the image will remain sharp and focused. These filters can create interesting, ethereal looking images in any scene that has movement.
Ultra ND filters are undoubtedly a specialist product. Using one successfully requires a good degree of understanding both of composition and exposure. They can, if used well, lead to stunning an original looking shots that would not look out of place in anyone’s portfolio.