Camera Lens Filters

Learn how to control your camera's flash system through the available camera flash modes

So, what is the use of camera lens filters in digital photography? - you might ask ...

The first step in creating successful, natural looking images is to take into account the ways seeing differs from photographing .

Let's assume that you are hiking in the mountains and see a majestic landscape in front of you, your eyes act as little optical machines to register the scene but all that you see is enhanced and interpreted by your brain. Hence some of the splendour of the scene is supplemented by your mind.

If you lift the camera to the same view, you will get a completely objective representation of the scene, without any intelligent enhancements. The camera is just a little optical machine with no mind of its own. You might consider, yourself - the photographer - as the camera's brain employing different compositional and manipulation techniques to add intelligent interpretation of the scene on paper.

You can thus employ different types of camera lens filters, each changing the light that passes through the lens in some way to achieve natural and exciting looking photographs.

Camera lens filters were very popular before the advent of digital photography as some of the effects were not possible or easy to achieve in the darkroom.

Having a digital camera and being skilled at using an image editor like Photoshop, you may feel uoi no longer need lens filters because you can get similar results by digitally editing your images. However, there are many good reasons for considering using a few filters, the effects of which cannot be reproduce using digital editing techniques and the properties of which we will explore below.

Typical Camera Lens Filters Used in Digital Photography

There are a dozen types of camera lens filters, each with a specific function and effect on the produced image. Here is a brief overview of the most essential lens filters :

Type of Lens Filter	Benefits and Main Use	Subject Matter
UV/Haze and Skylight Protective Filters	Provide lens protection Help get rid of haze and reduce blue casts when photographying subjects in the shade	Any
Neutral Density	Helps to extend exposure time	Flowing Water, Landscapes
Graduated Neutral Density	Helps to even out exposure and balance the sky and foreground in brightly lit scenes	Landscapes
Linear & Circular Polarizers	Help to reduce glare and reflections Help to make richer colours and improve colour saturation	Sky, water and foliage in Landscape scenes
Light-coloured and Gradiant filters	Change White Balance Adding a 'warming' or 'cooling' light cast	Landscapes, Special lighting conditions
Special Effects	Diffusion filter helps soften the scene Infrared filter baths the scene in infrared light	Portraiture and Romantic Landscapes, Infrared Photography

Colour convertion filters can be skipped when using a digital camera, since you get these by adjusting the camera's white balance settings.

UV/Haze Protective Filters

The Auto Flash Mode option automatically fires the flash whenever the light level is low for a good exposure or when the main subject is backlit. This setting is the best choice for most shooting circumstances.

Flash On with Red Eye Reduction Mode

There are a dozen types of camera lens filters, each with a specific function and effect on the produced image. Here is a brief overview of the most essential lens filters :

There is also a downside to using a red-eye reduction mode - many subjects blink during the pre-flash, and then the second flash catches them blinking. Or sometimes subjects think that the first flash means the photo was taken and they move and the second flash fires to capture their movement on the photo.

To successfully eliminate red eye, you need an external flash that is positioned away from the axis of the camera lens. If however you do not have an external flash but only a built-in flash, the best strategies are to zoom the lens out to a wider angle, tell the subject to look directly at the camera, try to get close, or increase the overall room lighting.

On most cameras you have the option to turn red-eye reduction mode off.

Flash Off Mode

This camera flash mode turns the flash off so that it will not fire even if the light is low. You can instead use a long exposure to capture the image in natural light.

Fill-in Flash Mode

With the Fill-in Flash Mode, often called Flash On or Forced Flash , the flash fires every time a picture is taken even if there is enough available light to take the picture without flash.

You will select this camera flash mode when you want to filling in shadows when photographing in bright sunlight or when your subject is back or side lit. In such situations shadow areas can be so dark in the image that they show little or no detail. And when the subject is backlit or against a bright background, it can be underexposed.

Fill flash is also a good way to get accurate colour balance under unusual lighting.

Using the fill-in camera flash mode is also very useful when photographing room interiors, which may include a window and where the existing light alone leaves heavy black shadows. If possible, use a powerful flashgun in these circumstances and bounce the light off a suitable wall or surface not included in the picture. This will produce the most even fill-in effect for the scene.m

Slow Shutter Flash Mode

In very dim lighting conditions, flash images show a well exposed foreground subject against a black background. The Slow Shutter Flash Mode is designed to minimize this problem by leaving the shutter open longer than usual to lighten the background.

This camera flash mode works by firing a short burst of flash during a longer exposure to freeze objects while still allowing them to blur. If you want to avoid the blur, you will need to use a tripod or use this effect creatively.

This mode is best used for night portraits where the flash lights up the person and the long shutter is used to record the night or city lights.

Slow Shutter Flash Mode

Stroboscopic flash feature is usually set on the flash, not on the camera. It works by firing the flash a number of times at high speed to capture multiple images of the same subject in the same photograph.

This camera flash mode is often used in sports photography for motion studies of a moving subject i.e. golf swing.

High-Speed Sync Flash Mode

This feature is supported in some flash units and you will use it in situations where you want to use a shutter speed that is faster than the camera's flash sync speed. It works by firing numerous rapid bursts of light ensuring that the entire image is illuminated even at extremely fast shutter speeds.

The only drawback is that the feature minimizes the effective flash range so you can't be positioned as far from a subject. The higher the shutter speed you use, the closer you have to be.

Controlling Flash Exposure

Flash Exposure Compensation

Using flash can over or underexpose a subject and it is through the flash exposure compensation that you can manually control the amount of flash light cast over your subject without changing the camera's aperture or shutter speed.

This is an ideal way to balance flash and natural light when using fill flash and to correctly expose scenes or subjects that are darker or lighter than normal. It can give excellent results as it allows you to make more details visible in the shadows, while minimizing the "flatness" that can occur when full flash is used and all the shadows are removed.

The exposure compensation function often lets you vary flash exposures plus or minus 2 stops in one-third stop increments.

Flash Exposure Bracketing

This feature is similar to Autoexposure Backeting. In situations where you might find it difficult to obtain a proper exposure, the flash exposure bracketing allows you to take a series of two or three consecutive pictures exposed at slightly different settings above or below the exposure recommended by the autoexposure system. The flash output changes with each image while the background exposure level remains the same.

Flash Exposure Lock

Flash exposure lock is very similar to AutoExposure Lock and can be used to set the flash exposure for an important subject area in your image.

The feature works by firing a preflash that is used by the light metering system to calculate correct exposure for the primary subject area and the resulting flash settings are locked in. You can then recompose the scene or make exposure or focus adjustments without losing your flash exposure data.

Flash Exposure lock feature is extremely useful when the main subject is off-center or there is a strong backlighting.

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