Photography - A guide to N.D. filters
Updated: May 4, 2020
I was asked the other day "what filter did you use for that picture", to which I replied a Lee 0.75 hard graduated filter. They looked blankly at me and somewhat confused, I asked them what was wrong, and their reply astounded me......."I've not seen that on Instagram, where do you get it from".
To say I was horrified was an understatement, so I decided to explain what a filter actually is to a photographer and not a person of the Instagram generation.
A Neutral Density Graduated filter is a small piece of glass or resin (much better optically) that mounts on the front of your lens, half is crystal clear and half is darker depending on the grade you pic.
The idea is that it covers the sky portion of your picture which is usually a much brighter space than the ground. This enables you to get a more balanced and better overall exposure of the scene in front of you which as any landscape photographer will know, its an essential piece of kit.
Before I started using these I would have a scene that was either full of a beautiful coloured sky and everything else was so dark you couldn't make it out, or a nicely exposed foreground and a bright white over exposed sky, frustrating wasn't the word !
Then I discovered Neutral density filters and the difference was incredible ! Suddenly I was able to take balanced shots with everything exposed to match, well thats not quite how it happened as I started by falling for the biggest mistake of using a far too dark filter, but the concept was grasped and the use of filters was quickly taken up on every shot with very good results.
The filter is mounted to the front of the lens with an adaptor ring that screws into the lens thread, and then a holder kit which clips to it. The filter its self slides into the holder and can be moved up and down according to the level of your horizon.
This will darken the sky according to the level of filter you have selected, they usually go up in .5 of a stop increments.
Now of course there are some scenes which have a nice flat horizon, for which a HARD ND Grad is the perfect choice, but what about those scenes where there are hills etc...and an uneven horizon, well for that you can use a SOFT ND grad filter which as the name suggests has a softer graduation so it blends a little easier, that said these will still leave a darker exposure on elements that they are covering.
The trick with filters and more importantly the shot, is to use them to your advantage, when the scene needs them, some scenes are better shot without and trying to expose for the elements that are most important for you in the finished product. Above all control the light for your situation and use it to your advantage, there are many pictures where a strong silhouette really adds to the feel of it all and the drama.