Tag Archives: Graduated neutral density

Using a neutral density filter

ND filters can be used to produce some great images

Lee Filters – Big stopper neutral density filter reduces the light by ten stops. You can produce great images like this one from the video.

Sometimes you need a long exposure…

However, to take a very long exposure in daylight will mean too much light will burn out your picture. So you need to turn down the incoming light. For that you use an ND Filter. Here is how they are used.

Remind me, why do I need this?

Remember, shutter speed controls movement blur. If you want to show a car looking blurred as it goes past you might set the shutter speed to about a fifteenth or thirtieth of a second. But what if you want to capture a much less obvious movement or a really slow movement? Say two minutes? Well, normally the amount of light coming in will burn out the shot. Of course you can use a really small aperture (eg: f22) and let less light into the camera. But on a bright day two minutes will still burn out the shot. This is where Neutral Density (ND) filters come in. They are specially darkened filters that cut the light down allowing you to extend your exposure. With one of these you can do some awesome effects.

10 stop Neutral Density Filter (video)

In the video we see the making of a picture (above) by using the Lee Big Stopper Neutral Density Filter. This ND filter is very dark, which takes down the light by 10 stops. It creates a great effect on of the water swirling under the pier. This is the darkest type of ND filter.

ND filter strengths

ND filters can reduce the light entering your camera for up to 10 stops. This allowed 2 minute exposures in the video. However, there is also ND2, then ND4 and ND8. Other strengths exist, but these are the most common. They allow you to have shorter exposures so you can adjust the exposure to the needs of your shot. You can also put them together so an ND8 + ND2 gives you an effective ND10 – the strength in the video.

ND Grad.

Another of these type of filter is the graduated Neutral Density, or ND grad. The use of an ND grad is quite specific. It is used to reduce the incoming light from the sky when you have a bright sky and dark ground. If you expose for the ground the sky burns out. If you expose for the sky the ground is too dark. The ND Grad. helps prevent the sky burning out.

The ND Grad. is dark at one end and clear at the other. The two zones meet in the middle where the clear graduates into grey. Put the filter over the lens so the line of clear/grey graduation lies on the horizon, darkening the sky. Now, you can expose for the scene and get even light distribution. The next video will show you how this type of ND is used.

Mike Browne  External link - opens new tab/page
Problems?

No, filters are simple and easy to use. There are some important things to remember…

Always use a tripod. It is impossible to hold a camera steady for more than about half a second. After that your image will start to get blurry.

You need to be quite precise about lining up ND Grads with the horizon. Take a little practice before going out to do the BIG shot.

The darker the ND Filter the more there is a tendency to impact on the white balance. Sometimes you get a blue colour cast, sometimes a red one. You can remove this in post production if you are using the RAW file format. Alternatively you can test the filter with your camera and adjust the white balance setting in-camera to correct for the aberration. Most of the stronger ND filters have this colour-shift tendency. it is exaggerated by the sensor type. CMOS sensors tend to magnify the effect.

Sometimes getting the exposure right is a matter of experimentation. Take a few test shots and make sure you do some “Chimping”.

If you are buying ND filters, especially ND Grads buy square ones. You can buy adaptors for these to fit any lens and it allows you get creative in more ways than round, screw-on filters that only fit one lens.

There are many different kinds of filters which produce a huge range of fun effects in-camera. Many of these effects cannot be processed into the shot later. The square filter system shown in these videos allows you to expand your collection and develop a new set of skills without buying an expensive filter for each lens.

ND Filter set…

3 full ND filters
3 graduated ND filters
Full fitting kit for a range of camera
and lens sizes.
10 Adapter Set + 6 Filter ND2 ND4 ND8 G.ND2 4 8 For Cokin P Canon Nikon Sony LF6

Please leave any questions or comments you have about these in the comments below.

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By Damon Guy (author and Photokonnexion editor)

Damon Guy - Netkonnexion

Damon Guy (Netkonnexion)

Damon is a writer-photog and editor of this site. He has run some major websites, a computing department and a digital image library. He started out as a trained teacher and now runs training for digital photogs.
See also: Editors ‘Bio’.
By Damon Guy see his profile on Google+.

Pure white featureless skys? How to tone them down…

• Cokin neutral density filters (graduated) •

• Cokin neutral density filters (graduated) •
A quality set of filters that can be adapted to fit any lens size.
Buy: Cokin H250A ND Grad Kit

When your sky is too bright its a problem!

You lose all or most of the detail and your foreground is starkly highlighted by the blown out sky. The way to overcome blow out like this is to use various techniques with neutral density filters. All landscapers come across this problem at some time. The best way to overcome the issue is to tackle it head on in-camera. The best way to do that is to use “graduated neutral density (ND) filters”.

What are ND filters?

Neutral density filters are glass filters that you reduce the incoming light. They do this without affecting the colours in your shot. For blown out skies you want to reduce only the incoming sky light and allow the foreground to expose properly. The Graduated ND filter will allow you to achieve that.

In the picture above you can see the top half of each filter is dark. The bottom half is uncoloured glass. The trick is to place the filter in front of your lens. Place it in such a way that the line separating the dark and light lies on the horizon between the ground (proper exposure) and the bright sky which will be toned down by the filter.

If the sky is blown out in your picture the light is brighter than the camera can cope with. Normally that will be two stops of light or more above your exposure of the ground. The ND grads. normally come in three strengths. ND2 (two stops), ND4 (four stops) and ND8 (eight stops). Each stop of filtration is equal to half of the total light. An ND2 reduces the light by a quarter. An ND8 will cut down the incoming light to 1/16th of the light.

Video – Graduated ND filters for Landscape Photography

In this short video Tony Sweet demonstrates how he balances the dynamic range of a landscape composition using a graduated ND grad. filter working in a wooded valley. He wants to brighten the foreground with a long exposure. This would lead to the distant trees being too bright and would show burnt out spots. He uses a great technique to make the right light conditions…

Recommended purchase

I have been using Cokin filters for years. They are high quality filters that fit into a filter mount screwed onto the front of your lens. I prefer this type of fitting. It is simple to change filters and you can adapt graduated filters to the position you want quite easily. Round filters are far less adaptable and tend to be much more expensive.

If you want to buy an ND grad set of filters here is the kit I recommend…
Cokin H250A ND Grad Kit

You will also need to buy an adaptor for your lens to fit the filter mount. You can buy them singly…
Cokin filter mounts and lens adaptors

You can also buy a complete adaptor kit so you can adapt your filters to fit any one of your lenses…

 

 
If you feel like going the the whole way you can buy a kit that will cater for all your filter needs (including mount and adaptors) try this great kit…

 

By Damon Guy (author and Photokonnexion editor)

Damon Guy - Netkonnexion

Damon Guy (Netkonnexion)

Damon is a writer-photog and editor of this site. He has run some major websites, a computing department and a digital image library. He started out as a trained teacher and now runs training for digital photogs.
See also: Editors ‘Bio’.
By Damon Guy see his profile on Google+.

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