How to use a 10 Stop Neutral Density Filter
Lots of people have asked me the correct way to use a 10 stop filter. Whilst there are two main variables that do not make it’s use an exact science - available light and flow of water - there are a few basic principles that you will need to stick to if you want success.
Although your 10 stop filter has many uses, this Article will concentrate on how to use it to capture slow moving water shots.
Now you’ve got it what do you do with it?
If you were like me you most probably have anxiously waited a couple of months for your 10 stop filter to hit the doorstep. Everyone in your circle of photography friends has talked about it and now it’s arrived you’re unsure on how to use it properly. This short article will go some way towards you getting a lot of fabulous images and making you feel as though you have definitely purchased wisely.
10 stop filter uses
A 10 stop filter is a long exposure filter that reduces the amount of light entering your lens by approximately ten stops. This gives you a broad scope to create incredible images using slow shutter speeds or wide apertures.
The main use for a 10 stop filter is making everything that is moving within your image blurred and ghost like and is very effective on water especially on waterfalls, rivers and streams and the sea. They can also be used within the city environment when photographing cityscapes and traffic where you want to remove people etc.. But as I mainly use my 10 stop filter for landscapes then this is what I am going to concentrate on within this article.
Positioning of your 10 stop filter
The two images below show you both sides of the 10 stop filter. Image 1 shows how dark the actual filter is and Image 2shows you the ‘sponge’ seal that is used to seal the filter against the filter holder. You must make sure that all of the sponge is firmly positioned around all of the filter holder and positioned evenly on to the holder.
Correct positioning of the filter is crucial to getting great results. If this is not positioned correctly then, due to the very slow shutter speeds you will be using, light can ‘leak’ into the image and cause ‘orange’ over exposed areas around the perimeters of the filter. Image 3 and Image 4 show the correct positioning of the filter on the filter holder.
Due to the strength and darkness of the 10 stop filter you cannot expect your lens to pick up and focus on anything within your image after it has been positioned; therefore you will always need to pre focus before correctly placing your filter as described in the ,above paragraph. After focusing and positioning your filter, you can now switch your lens to manual focus which will stop your lens ‘hunting’ for a focusing point when taking your image. There is, however, one exception to the above. If you camera has exposure simulation within ‘live view’ then you should be able to reduce the shutter speed to a slow enough speed giving you a correct exposure that should make your image appear on your screen which will then allow your lens to focus automatically. This again is really crucial to obtain great images. My preferred method of working is to shoot on manual mode at F11 and set my camera to Exposure Simulation within ‘live view’ and set my lens to auto focus.
Water movement and shutter speeds
Generally speaking the slower the water movement the slower the shutter speed needs to be to obtain that ‘milky’ effect we want to achieve. A word of warning, if you’re photographing fast ‘white’ water then if you shoot on too slower a shutter speed then it’s very easy just to capture a mass of over exposed white areas that are not very complimentary. So when you’re checking out suitable areas to use your 10 stop filter just bear in mind that you want to photograph moving water that doesn’t contain too much ‘white’ water to get your best results. Even very slow moving water can look great if you shoot it at very slow shutter speeds. Over the years, I have found the best shutter speeds have been between 2 seconds and 8 seconds but again I must emphasise that it’s all to do with the light conditions and the speed of the water. Obviously, with these sorts of shutter speeds a tripod is an essential piece of kit and these kinds of shots should not be attempted without one. A remote release or shutter release cable is also invaluable to obtain good crisp images. For more information see the Checking Results paragraph below.
When you start to use your 10 stop filter you may see a ‘blue cast’ to your images as shown in Image 5 . This is normal and can be corrected. Correction is all to do with ‘White Balance’. There is only one word that explains white balance and that is Temperature. It’s calculated on the Kelvin scale where Sunny is around 5200K, Cloudy is around 6200K and Shade around 7200K and these can be set under the White Balance category within your menu structure. Unfortunately Shade at 7200K is sometimes still not warm enough to reduce that colour cast. Nearly all DSLR’s have a setting within the White Balance menu structure that allows the user to set their own value within the Kelvin scale. Again, this is to do with personal preference but I think a setting of around 9000K gives the best results. As this is under your own control then please experiment around this figure to give the results that are to your own liking.
People who know me or have purchased my work or have been on one of my one to one courses know that the preferred aperture and ISO for landscape photography is F11 and 100 respectively. So this is my starting point at any of my slow moving water locations. Deciding shutter speeds can be tricky and when using the 10 stop filter you invariably will be shooting at speeds far slower than 8 seconds. If the shutter speed is far too slow and you’re not getting the affect you want, you can always increase the ISO to a higher value making the sensor more sensitive. This will increase the shutter speed to hopefully give you the effect you want. If not, again change the ISO to suit. If you’re not shooting slowly enough (I doubt that this will be the case though) you can always change the aperture to a higher value (narrowing the aperture – less light therefore shooting slower) maybe to F16 or F22 to get the effect you want but again change to suit.
Image 6 is an image that I took near Ashness Bridge one autumn day and used a Lee Big Stopper (10 Stop filter). It was taken at ISO 800 at F11 at a shutter speed of 6 seconds with a white balance set to 9000K.
Getting your milky effect water, is I’m afraid, not an exact science but given the right starting point and the knowledge to know what to do if you’re not getting the right effect you want with your10 stop filter can get you some stunning images that you will be very proud of. Some people love this effect and some people hate it but now you’ve purchased the 10 stop filter this article will hopefully go some way towards you obtaining these classic images that in my opinion can look very effective when used on the right location.
© Martin Lawrence Photography 2013