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Photography Tips 3 – ND Grad Filters

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This is the third in a series of articles discussing some of the photography techniques I’ve learned and employ when I’m out on a shoot.

Imagine trying to take a picture of a hillside on a sunny day. The sun is high in the sky, the clouds are fluffy and white, the hill in front of you is dark and rocky towards the summit and lush green grass as it approaches you. There are a few trees near you casting shadows too. Lovely.

You take the shot but when you look at the picture it’s nothing like what you see. Most likely the sky will be completely burned out (i.e. totally white) so you can’t see the nice fluffy clouds and blue sky. Alternatively you will be able to see the sky but the foreground will be so dark you can’t see any detail. Or you’ll just get a “somewhere in between” where the rich textures and colours from the sky and foreground will be gone leaving a flatter, less interesting picture.

The problem is that while the human eye can easily resolve massive differences in light – from the very bright sun to the very dark foreground – the sensor on a camera can’t. Your eye can resolve around 10 stops of exposure in a scene but a camera can only really resolve a couple. Note: a one-stop increase in exposure equates to double the amount of light, so 2 stops is 4 times the light, 3 stops is 8 times and so on. To save the maths, basically your eye is one hell of a lot better than a camera!

Yet when you see a landscape photo taken on a bright day, it looks exactly like it does to the human eye. So what’s going on? Well take a look at this photo taken on Ilkley Moor:

Blue Haze

Notice that for one thing, it’s taken directly into the sun, which is clearly very bright. If I took this shot with a compact digital camera it would realise how bright it was, close down the aperture and set a very high shutter speed to cut down on the light. The end result would be pretty much blackness with a very much darkened down sun in the top corner. Not ideal.

For this I used a couple of Neutral Density Graduated Filters (called ND Grads for short). You can see what they look like below:

ND Grads

They graduate from clear to a dark shade (left) and fit onto a filter holder that you attach to the lens (right). The idea is you line up the horizon with the barrier between clear and dark on the filter and that tones down the brightness of the sky. The brightness of the sky is now much closer to the rest of the picture (within a couple of stops as I mentioned above) so the camera can now take the picture and pretty much recreate what you see with the naked eye. You can double up and use more than one filter at a time to cut down the brightness even more, as I did on the photo above.

A cokin p ND grad kit (which will do for most SLR digital cameras) costs around £30 including the filter holder so it’s not an expensive piece of equipment – but for landscape photography it’s probably one of the most important!

Next: How To Hold A Camera.

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Creator of John's Background Switcher. Scotsman, footballer, photographer, dog owner, risk taker, heart breaker, nice guy. Some of those are lies.

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