The 10 stop filter is quickly becoming that must have gadget and with recent offerings from Lee with the Big Stopper and Light Craft Workshop with their Fader ND mark II there is even more competition out there, but many of you may not be aware that the humble 10 stop filter has been around a lot longer than the current craze, in fact I have been using a B+W ND110 10 stop filter for the last 3 or 4 years.
Regardless of who makes the filter they all work in a very similar way and generate pretty much the same result, such as dramatic windswept skies and misty water which help to create an almost surreal look to the photograph, it is the truth just maybe not as we perceive it and to be honest I love the effect.
The filters out there on the market fall into two categories… circular screw in filters such as the B+W ND110, Heliopan ND3.0 and Light Craft Fader and square filters to fit into a filter holder such as the Lee Big Stopper and the Hitech 10 stop. From my experience the pros of using the screw in filters such as the B+W ND110 is that they will fit inside a lens hood, this can be useful when shooting in the rain as it helps to keep water off the lens (maybe this is just me who tends to photograph in less than clement weather).
The con with the screw in filters comes when you combine them with a graduated slot in filter like those from Lee, as the screw in ND filter attaches to the lens first you will not be able to position the grad when in place (although the live view systems on the Canon 5D MkII and Nikon D3S can see through the 10 stop filter, but only in bright light). The usual way around this is the position the graduated filter first and then remove the filter assembly without moving the graduated filter in its holder, attach the screw in ND filter and then re-attach the filter holder / graduated filter. When using a square filter such as the Lee Big Stopper you can simply slide it in and and out of the holder as required, making it quicker if you want to recompose a shot or check focus or re-position the graduated filter.
Despite what you may have heard especially about the Lee Big Stopper these 10 stop filters are not pure neutral density, if you take a shot without the filter and then a shot with a 10 stop filter and only change the shutter speed so the white balance remains constant the two photos will look different. The Lee Big Stopper for instance has a cool blue colour cast, the B+W filters have a warm orange colour cast and I am sure the Hitech, Heliopan and Light Craft Workshop filters will have their own colour casts too. Although to be honest this is not too big a deal if you are shooting in raw as you can change the white balance to correct the colour cast.
The final point on these 10 stop filters is that most of these filters are not in fact 10 stops, the documentation that comes with the Lee Big Stopper quotes the actual strength maybe between 9 1/3 and 10 2/3 stops and from testing mine it came out at 10 2/3 stops which incidentally is the same as my B+W ND110 10 stop filter. To determine the exact exposure all you need to do it set the camera up on a tripod and meter the scene in front of you, then apply the filter and add 10 stops (or whatever the filter strength is) and take another exposure so if the initial exposure was 1/30th of a second this should be 30 seconds with a 10 stop filter applied, then compare the two images on the camera. If the second exposure is darker trying adding a 1/3 of a stop with would be 40 seconds, if its still darker add another 1/3, the second image is litter simply deduct a third until the without and with filter match. Knowing the exact strength of the filter make it easier to get exposure spot on when you are racing against the fading light.
N.B. I know the Fader ND Mark II filter from Light Craft Workshop is only 8 stops but for completeness I felt it should be included.
Neutral density filters or ND filters for short are without a doubt one of the most critical accessories I use when photographing the landscape, so much so it is not uncommon for me to carry anywhere between 4 and 10 of them with me at any given time. Neutral density filters are essentially grey coloured filters that reduce the amount of the light entering the camera, there is a vast array of neutral density filters out there and they can be broken down into two main categories, graduated and solid.
Graduated neutral density filters are usually square filters that are half clear and half neutral density with a smooth transition across the centre of the filter. These filters are designed for landscape photographers and help to balance a bright sky against a darker foreground. They are especially useful when photographing sunrise and sunset where you will often have a bright sky and a shaded foreground. These graduated filters are available in various different strengths which control how much they reduce the light by, the most common strengths are 1 stop, 2 stop or 3 stop although depending on the manufacturer these can be expressed as 2x, 4x, 8x for Cokin and Kood and 0.3, 0.6, 0.9 for Lee and Hitech. Not only are graduated filters available in different strengths but some manufacturers offer a choice how quickly the neutral density part of the filter becomes clear. The harder the line the harder the change from dark to light on the photo.
In the example below you can see the effect of using a 2 stop graduated neutral density filter and how it has helped to hold back the sky detail.
Solid neutral density filters are just that, a solid filter that reduces the light equally across the whole photo. As with graduated neutral density filters these solid filters come in an array of different strengths and are available as either square filters for use in filter holders or circular screw in filters that attach straight on to the lens. These filters are available in a broader range of strengths than graduated filters typically from 1 stop to 10 stops. The purpose of these filters is to increase the exposure time which can lead to wonderful effects especially when photographing around water. If the required exposure was 1/30th of a second by using a 3 stop ND filter you would extend this to 1/4 of a second, a 6 stop ND filter would give you an exposure of 2 seconds and a 10 stop filter would give you an exposure of 30 seconds.
The two photos above illustrate the effect of using a 10 stop filter to increase the shutter speed from a 1/15th of a second up to 60 seconds, the pier remains constant in both photos however in the long exposure on the right you can see the soft blurring effect of the sky and the sea. You can read more about Long Exposure Photography here.