Photography News Issue 58

Photography News | Issue 58 | photographynews.co.uk

Technique 47

Camera School Here we lift the lid on all things camera related, showing how to get better results from your CSC or DSLR, and providing all the info you don’t find in the manual. So, stick with us and you’ll soon be wielding your camera like a pro. This month, do you need hard or soft neutral density grads, and where should you position them in the frame?

Words & pictures by Kingsley Singleton

Poor use of hardgrad

Good use of soft grad

Neutral density (ND) grads are vital in helping photographers balance light levels across the frame. They block more light at one end of the filter than theother, sobright anddim parts of the frame can be correctly exposed in the same shot; for example in landscape photography to stop a bright sky losing detail. These filters come in different strengths, so all you have to do is match that to the difference in brightness between the light and dark parts, and you’ll have a much better exposure.We covered all this in detail in last month’s Camera School, so if you want a refresher, head back to that. This time, though, we’re going to look at the intricacies of using ND grads. There are twomain types ofNDgrads – hard and soft – though you can also increasingly find medium grads. It’s simplytodowiththerateoftransition from clear to filtered. As mentioned previously, an ND grad is clear at one end and darkened at the other, so, while a soft grad might take, for example, three or four centimetres of the filter’s surface to go from clear to filtered, a hard gradwill likely do this in one centimetre or less. A medium grad will be somewhere between the two. There’s no standardisation for these transitions, but they’re obvious to see when you hold the filter up to the light. WHICH TYPE TO YOU NEED? How steep, or rapid, the gradient you need to use depends on the scene in question, on the focal length of the lens you’re using and, of course, your intentions for the image. Though they seem obvious in your hand, the WHAT ARE HARD AND SOFT GRADS?

Images A hard grad works best on scenes with a fairly straight horizon (below left), but can be an issue in scenes the above, where part of the scene (here, the wall on the left side) is protruding clear of the horizon.

effect of soft grads is very subtle; for example the area of transition may cover most of the front element of the lens, and therefore most of the scene. This is useful if the horizon is broken, with hills, trees or buildings jutting into it. Conversely, if you’re shooting a scene with a flat horizon, a soft grad might take too long to filter the light. This is where hard grads come in. Despite their transitions looking almost unusably harsh to your naked eye, when placed on the lens, they’re more forgiving, and perfect for unobstructed horizons like low, distant hills, or the sea. Again this is due to the amount of the front element they’re covering – 10mm of transition on a lens with a 77mm filter fitting might be nearly 15% of the frame. Just as with soft grads, there are limitations; on broken horizons, likemountains, a hard grad will show as an unnatural line. Broadly, the longer the focal length or the smaller the front element of the lens, the more of the image the grad will cover. In the case of telephoto lenses you’re simply magnifying the graduated portion along with the scene, so it will look softer.

WHAT ARE REVERSE GRADS Another type of ND you’ll find is reverse grads – these are aimed are photographers shooting sunsets, where the brightest part of the frame is in the middle. They’re still darker at one end and clear at the other, but the middle is denser, so as to balance that area. You can actually get a similar effect by reversing another graduated filter over the first, leading to a darker band in the middle. To get a natural-looking effect, the grad must be positioned to suit the scene. This is why grad filters are physically taller than full NDs, allowing you to move them up or down to fit the scene. You can also angle them if needed, for example when shooting from a hillside. The grad should usually be placed near to the horizon as that’s where the change in brightness will occur, but with a soft grad it’s often better WHERE SHOULD YOU POSITION THE GRAD?

to place them a little lower. The one thing you really don’t want is an obvious strip of unfiltered light, such as when using a hard grad too far above the horizon. Conversely, too low will make the land look unnaturally dark. Judgingwhere you place the grad can be done by eye through a camera’s optical viewfinder, but what you’re seeing is the lens at its widest aperture, so the grad won’t be that obvious unless you use the depth- of-field preview button to show the effect of a smaller aperture. You can also do it by trial and error, shooting and reviewing images, but this can be tiresome with longer exposures, as well as annoying if you miss the best light having wasted time. Using live view is a good method, either on screen or via anEVF, as you should be getting a WYSIWYG view of the scene. HOWTO TELLWHERE THE GRAD SHOULD BE

NEXTMONTH WHAT DO POLARISING FILTERS DO AND HOW TO USE THEM?