Even the best of landscape photographers find themselves having to contend with the issue of the sky being a lot brighter than the ground featured beneath it in the same shot, making for an issue with exposure in that it really doesn’t matter what setting you select. Either the sky will appear too bright or the ground will be too dark.
All’s not lost however because you can graduate the neutral density filter as a quick and easy fix, known as an ND Grad. Circular ND Grads are indeed available, but the majority of these are rectangular or square in shape, a design feature which allows them to slip into the fitter holder that can be attached to the lens ending, this through the adaptor ring. While one half of the filter will maintain a neutral grey appearance, the other half is clear and it’s the grey section which reduces the amount of light reaching part of the film/sensor. This is how the magic happens.
ND Grads are available in a variety of densities (“strengths”), graded by the amount of light cut out by the unit’s darker portion. 0.6 ND grads come in as the most popular filters, reducing exposure by 2 stops. However, it’s perhaps well worth the investment getting two or three grads with different densities. This way you’ll be able to handle a good range of different situations.
Filters can also be combined to achieve greater densities if you have filters with several slots. For example, you can use the 0.3 ND Grad (1 stop) together with the 2-stop 0.6 ND grad to effectively create a 0.9 ND Grad that gives a 3-stop exposure difference.
Hard and soft gradations are also available, with the hard grads coming in useful for a horizon that has a very defined edge (like a seascape), whereas the soft grads show their worth when mountains, trees and the likes break the horizon.
Getting it right with the exposure
To get a feel for using an ND Grad, first shoot a couple of test landscapes so that you can establish the exposure difference between the sky and the land. E.g. if the landscape looks just right at 1/125 sec at f/16, but the sky looks better at 1/500 sec at f/16, this would mean that there is a 2 stop difference, making a 0.6 ND Grad ideal.
Once the landscape composition has been tweaked to your liking, insert the graduated ND filter into the filter holder, making sure to keep the grey section at the top. Take a peek into the viewfinder and then adjust the filter downwards until you’ve aligned the transition between light and dark with the horizon. Make sure the edges don’t spill over into the image frame.
The filter’s darker section effectively reduces the sky’s brightness, aligning its exposure with that required by the land. Now, all that’s left to do is set the exposure in the normal manner you would or you can even use that exposure which worked for the land in your test shot.
You’ll be happy to learn that you can get the landscape looking just right without the sky burning out.