If you thought the digital age meant you could do all your filter effects in your computer then it’s time to think again. Just like when you used film, filters are a great way of enhancing shots or adding some creative flair. Doing it at the time you take your images means you’ll spend less time altering your images later.

Each of your lenses should have a protective filter on them to ensure the last thing you damage if you knock or drop them is that precious front element. If you take the time to read the information that comes with your lenses you will see that most modern lenses require the use of only one filter at a time. As the size of the film area or CCD has changed, so has the size or thickness of the filters you can put on the front of your lens. Filters for digital lenses tend to be thinner.

Once upon a time you would have purchased a UV or Skylight filter, now it will more than likely be called a ‘protector’ filter as, thanks to your camera’s automatic white balance feature, you don’t need the subtle colour adjustments that the older filters made. To help bump up skies a polarizing filter is still the best option, but it can be used for more than just adding depth to your landscapes.

If you own several lenses with different filter sizes, buy filters for the largest filter size and adapter rings for the other lenses. If your biggest filter is 62mm and your smallest filter is 52mm then you’d get a 52-62mm adapter ring to save you doubling up on filters.

Types of filters

There are two main types of filters: those you screw to the front of your lens and those that use a holder and a ring to connect to your lens. Here are the top filters used on digital cameras, why you should use them and what effects they will achieve.

UV, Skylight or Protector Filters

The primary use for any of these filters is to protect the front element of your lens. UV filters cut down on the amount of blue that passes through your lens, helping eliminate haze and, for a film camera, giving a more even exposure. When using film, a Skylight filter gives marginally better skin tones thanks to its pink tone. Digital cameras react to light differently, as they automatically adjust for ‘white balance’. This clever adjustment for different light means that you don’t need to alter the light coming through the lens, since the camera already knows what the light source is. Hence the filter of choice when using a digital camera is a ‘Protector’ filter that doesn’t adjust the incoming light, but just offers protection for the front element.

When wouldn’t you use one? The only time you’d take this filter off is when you are doing very long exposures, as you run the risk of getting a reflection between the filter and the front element that could ruin your image.

Circular Polariser

This is the best filter for doing a number of things: it helps give that dramatic effect of deep blue skies and can take reflections from glass and water. This dark filter also robs you of two stops of light – two shutter speeds slower – so it pays to watch your exposure when using one. There is a benefit here, though. Have you ever been in the situation where you want to use a slower shutter speed but the light has been too bright? Screw on your Circular Polariser and you instantly cut back the exposure. Next time you want to get that fuzzy effect of moving water, use your polariser to help lengthen the exposure.

Linear vs Circular: You might feel tempted to buy the cheaper linear polarizing filter for your digital camera, but it wouldn’t be a wise move. Linear Polarisers let the light waves through in straight lines, but due to the nature of your camera’s light meter you may get misleading exposure information. Most digital cameras require Circular Polarisers that allow the light through in a circular motion.

When wouldn’t you use a Polariser? As useful as the polariser is, you can overdo it. Because you lose two stops of light you need to be careful when using flash. If shooting inside or in low light conditions it pays to use a tripod. You have to be careful with lenses wider than 24mm as you can get vignetting when the edge of the filter creeps into the picture. You can actually buy a thinner polarizing filter made specifically for wide-angle lenses; consult your lense’s handbook for the manufacturer’s recommended filters.

A Circular Polariser is a must for any Kiwi camera kit. If you don’t already own one make it your next purchase.

Graduated Grey and Graduated TobaccoDP 17 Filters Art of Glass Panel 2

Graduated filters help when you want to make the exposure for the sky similar to that of the foreground. Generally there is a 1.5 to 2-stop difference between your foreground exposure and that of the sky. To give a natural effect you would use a graduated grey filter, but to liven the image up a touch a graduated tobacco filter does a great job. You will see this filter used to great effect on TV programmes such as Top Gear, and these filters are used commonly in magazine advertising, too. The warmer tone of the Tobacco filter livens up the sky but be careful not to let it dominate the scene.

Taking two photos with your camera and metering one for the sky and one for the foreground then blending the two images together in Photoshop is the modern and logical solution to this age-old dilemma. The difference is that it takes more time doing it in the computer than doing it in your camera. Planning is the secret to success. Map out your ideas for the shoot and then choose the lighting and time of the day that suit the image

Neutral Density Filters

When you’re shooting in bright light but want to achieve a longer exposure, neutral density (ND) filters are invaluable. They come in a variety exposure values: ND2 = -1stop, ND4 = -2stops, ND8 = -4stops, and ND64 = -8stops of light. Architectural photographers quite often use these filters either to give the feeling of movement or to eliminate people or cars from a scene. Reducing the exposure to one-quarter of a second will give people moving in the fame a blurred look and create the impression of motion. Make the exposure even longer by using a darker ND filter and people moving in the scene will disappear completely.

You could even combine this with a Polariser to get a little more control over the exposure and make it longer. If you use a wide-angle lens and a combination of these filters to get longer exposures, you may have to take into consideration the fact that some vignetting may occur.

These filters will help give that furry effect when shooting water, or aid the length of your exposure when capturing cityscapes at night to get those long, drawn-out head and tail light effects of moving cars.

Close-up Filters

This series of three filters is like a magnifying glass for your lens. They come in diopter ratings of +1, +2 and +4 and can be used singularly, as a pair, or all three together. Using the +1 and the +2 gives a +3, and using all three gives a +7 for the closest possible picture. These are cheaper than a macro lens and a lot easier to carry. The easiest way to use them is to operate your camera in the manual focus setting and move yourself or your camera on a tripod into focus. Use them to shoot larger insects, coins and stamps, etc. Have you ever thought of photographing your jewellery for insurance purposes? These will help no end.

The down side with close-up filters is that they rely on you knowing what to do with depth of field. You need to close the lens down to get more of your image in focus. If your camera has a depth of field preview button, then press it to see how much of the scene will be in focus. It is also beneficial to use a tripod, as the more you close the lens down the slower the shutter speed will be. Juggling film speed to a higher ISO will let you shoot at a faster speed but noise build up will mean a loss of image smoothness.

Care and Maintenance

Like any optical surface on your camera, filters need to be kept clean. The less dust on them the better your pictures will turn out. If you encounter a speck of dust, resist the urge to wipe it with a micro-fibre cloth; use a blower brush first. The new high volume brushes designed for digital cameras work best. If this spot of dust proves more persistent then you will have to resort to wiping the lens with your micro-fibre cloth. Micro-fibre cloths can work a treat. The trick is to do as little polishing as possible.

The more you rub the filter, the more static you build up, and static will make more dust stick to the filter… Cokin filters are an acrylic plastic and are susceptible to scratching, so it pays to handle them with care. You slide them into a holder and the edges tend to mark, but the marked areas are well clear of the picture-taking part of the filter. Keeping the filter cases clean will aid longevity, too.

If you happen to drop your lens or fracture the filter, don’t try unscrewing it if the edge is dented; take it to a service centre and let them remove it. If the outer ring isn’t dented or damaged but the filter glass has broken, carefully remove the glass and then unscrew it from the lens. Removing the glass first will prevent the filter scratching the lens when you turn it to release it. If it appears too tight to unscrew, press the filter ring against the sole of a rubber-soled shoe or a rubber mat then turn. Hopefully the extra area of pressure will help release the ring.

Will your camera fit a filter?

Filters are not restricted to SLR cameras. A lot of new digital compacts will also accept filters with the help of an adapter. Sony’s H series cameras come with an adapter to let you put other lenses onto these big zoomed cameras, but they will also let you screw a filter on. Canon, Nikon, Panasonic and Olympus also offer models that either come with an adapter or to which an adapter can be added. Some compacts have the advantage of being able to take infrared shots with the aid of a Hoya R72 filter. This almost oblique filter only lets through near-infrared light that is ‘visible’ above 720 nm. The effects are quite eerie, with grass recorded as almost white and blue skies rendered black.

Conclusion

Ultimately it is up to you whether you do your work on a computer or take the challenge of getting it right in the camera at the time of shooting. Whichever path you choose, it will add another dimension to your photography and will help foster your creative flair.

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