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.
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 you no longer need camera lens filters because you can get similar results by digitally editing your images. However, there are many good reasons for considering using a few camera lens filters, the effects of which cannot be reproduce using digital editing techniques and the properties of which we will explore below.
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 camera lens filters :
|Type of Camera Lens Filter||Benefits and Main Use||Subject Matter|
|UV/Haze and Skylight Protective Filters||
blue casts when photographying subjects in the shade
depth of field in very bright light
|Flowing water and other subjects in motion , Landscapes, Street Photography|
|Graduated Neutral Density||
||Still and Motion Photography, Landscapes|
|Linear & Circular Polarizers||
|Sky, water and foliage in Landscape scenes|
|Light-coloured and Gradiant filters||
|Landscapes, Special lighting conditions|
in infrared light
Colour convertion filters can be skipped when using a digital camera, since you get these by adjusting the camera's white balance settings .
Ultraviolet light adversely affects the camera's exposure by reducing contrast. Thus Ultraviolet (UV) filters are designed to get rid of the haze and improve contrast by absorbing the ultraviolet light that the digital camera's sensor/film picks up but is invisible to the human eye. This type of filter is especially useful when photographing landscapes on a hazy day or taking images from airplanes. The UV filter is not essential if you are using a digital camera as the digital camera sensors are not as sensitive to UV light as compared to film cameras.
Skylight filters, on the other hand are designed to reduce the excessive blue cast that frequently occurs in outdoor photography, especially in shade under a clear, blue sky. It also keeps skin tones free of colour reflections from nearby objects such as the shade of foliage.
Nowadays UV and Skylight filters are primarily used to protect the front element of a digital camera lens from dust, moisture, scratches and breakage since they are clear and do not noticeably affect the image.
Most of the
damage done to camera
lenses occurs when they are improperly cleaned.
If you decide not to purchase and use a protective lens filter, use a soft clean cloth to clean the lens. Old cotton t-shirts make excellent cleaning cloths.
If you clean your lens often, consider buying a lens cleaner kit that has a soft cloth plus a small bottle of cleaning liquid. Avoid 'scrubbing' the lens because you can remove or scratch the coating on the lens.
Neutral density (ND) filters are designed to reduce the amount of light that gets to the image sensor in your digital camera without affecting the colour. Since it dims the whole image, it allows you to keep your shutter open a bit longer or set a wide lens aperture while avoiding overexposure in brighter conditions.
If you have ever seen a photo where the water looks like a silky stream of fog rolling over rocks, then most probably that photograph was taken with the help of a neutral density filter. Also, achieving shallow depth of field in bright light is very hard. Using a neutral density filter, you can not only slow action down enough to get the effect of a soft blurred water , but you can also improve the background blur behind your subject - a highly desirable feature for many photographers.
Utilising a neutral density filter can be very handy when you want to make moving objects less apparent or even invisible in a scene. Imagine that you are trying to capture an image of a building but you find the moving cars and people in your scene distracting. Using a higher grade neutral density filter will allow you to shoot at a longer exposure where any individual person or vehicle will not be in the image long enough to register.
Generally, when you use a neutral density filter, you also need to use a tripod because you will be shooting with slow shutter speeds.
Experiment with shooting water, and different moving objects. Why not try your hand at our 'Making Flowing Water Turn to Silk' photo assignment and share your results with us.
Neutral density filters come with various assigned filter factors which indicate the amount of light reduction. Be aware that different manufacturers label the filter factors differently making it sometimes difficult to understand how much light a given ND filter blocks. The effects are the same, only the labelling is different:
|Amount of Light Blocked in f-stops||Amount of Light Blocked in Fraction||Nikon, Hoya, B+W and Cokin||Tiffen, Lee||Leica|
|1||1/2||ND2, ND2X||0.3 ND||2X|
|2||1/4||ND4, ND4X||0.6 ND||4X|
|4||1/16||ND16, ND16X||1.2 ND||16X|
|5||1/32||ND32, ND32X||1.5 ND||32X|
|6||1/64||ND64, ND64X||1.8 ND||64X|
As with most filters, ND filters can be stacked to combine the effects of more than belowone, as long as the additional filters in the pack are not so thick that they become visible in the image, thereby cutting off corners. This is an effect called vignetting.
If you use more
than one filter at a time (generally not recommended),
vignetting can be a real problem.
To avoid vignetting, use a step-up ring so that you can use a larger filter.
Neutral density filters also come in a graduated variety (sometimes called split ND filters) where the top half (or bottom half or one side, if you rotate it) has neutral density, and the other half is clear meaning that it passes 100% of the light.
They are particularly useful for balancing the sky and foreground in a scene so that both are properly exposed. In most cases, the sky is much brighter than the foreground. A graduated ND filter, with the dark portion rotated on top, can even out the exposure for the two halves, making those washed-out clouds visible again.
Image courtesy of Amazon.com
The graduated ND filters come in many varieties, but these can be separated into two main categories based on how quickly the filter blends from dark to light:
Soft edge and Hard edge
You would use a hard edge GND filter in a scene where there is a sharp division in brightness, like a dark land with a horizon to a bright sky but make sure you place the blend carefully to match the division in the scene.
On the other hand, a soft edge GND filter provides a wider, smoother change from light to dark. It is used when the light and dark portions in the scene are not distinctly separated - one example will be a scene with a mountain and sky. The soft edge GDN filter is generally more flexible and less noticeable than a hard edge.
You can also have center-spot or radial blend GND filters that are slightly opaque in the center and are clear at edges to remove light fall-off at the lens' edges ( the vignetting effect we mentioned earlier).
The polarizing filter is very useful for reducing glare or sheen of light reflected from shiny surfaces such as water, glass or glossy foliage in a scene or when shooting through a glass window to remove reflections.
No Polarizing Filter
Polarizing Filter Used
In addition, these camera lens filters can give improved clarity and colour balance of your photographs as they can help reduce the contrast between land and blue sky in a scene. They can enhance or deepen the intensities of colours such as a blue sky, red and orange leaves, or green trees and plants.
But they can be tricky as the polarizer's effect will vary depending upon your camera's angle to the sun.
Too much polarization can increase contrast and colour saturation in a photograph so much that it can look unnatural. Until you have gained some experience with a polarizer, shoot the same picture with varying amounts of polarization so that you end up with a photo you like.
The strongest effect from a polarizer occurs when you shoot at a right angle to the sun. This means that if the sun is directly overhead, the polarizing effect will be greatest near the horizon in all directions. As you turn or rotate the filter more toward or away from the sun the effect will be less as the filter will block less light to your camera’s image sensor.
Be aware that your camera may also compensate for the darker skies by increasing exposure, which causes clouds to lose valuable detail, so you will want to take a quick look at the histogram (if your camera has one) to make sure your exposure is correct.
A polarizer can cut down on the amount of light to your camera’s image sensor ranging between one and three stops. This increases the risk of blur in the image if the camera is handheld as well as may make some action shots very difficult.
When using a polarizer filter and you want to view its effect on your image, your best bet is to look on your camera's LCD monitor because you will not be able to see the change through an optical viewfinder.
Additionally, using a polarizing camera lens filter on a wide angle lens can produce uneven and odd-looking results.
There are two types of polarizing filters generally available differentiated by the way they handle light: linear and circular. Your best choice is to use a circular polarizer because some autofocus and metering mechanisms in digital cameras may not work properly with a linear polarizer.
The use of these camera lens filters is much less important with digital cameras, since colour balance problems can now be addressed with image-editing software after the image is captured, or adjusted with camera's white balance settings as the image is captured.
There are a lot of different camera lens filters that produce special effects, including star-like points on highlights, prisms, special colours, and so forth. But we will concentrate on two particular types: diffusion and infrared filters.
A diffusion filter (also called a softening filter) will change the light to create the effect of a dreamy haze and reduce contrast thus softening the subjects in an image. This camera lens filter is most often used for portraits, but you can use it on anything you want to soften. For instance, you can soften even the hardest metal and dark coloured subjects taken at midday.
These effects can be achieved by post-processing the image with software, however the ending result may be noticeably different. It is especially useful to use a diffusion filter when there is too much contrast in a scene rather than rely on post-processing for contrast reduction. This might not be possible if the dynamic range of the digital image sensor is exceeded.
Many people are fascinated with the world of infrared photography. The reason for this lies in the unique quality of the images it produces, giving unusual and unreal tonality, enabling you to produce a new and different view of often otherwise ordinary subjects.
There are various types of infrared filters which are really dark - to block all visible light . With a film camera in addition to using an infrared filter you will need to use a special infrared film that can record the image.
With the advent of digital cameras it is now possible to take infrared photographs with many digital cameras and greatly simplify the infrared photography process. Infrared images are much easier to shoot digitally compared to shooting with infrared film in a film camera. However, you must use an infrared filter that blocks visible light and be prepared to shoot at very slow shutter speeds (because very little light is left for the exposure) which in most cases requires a tripod. The required long exposure makes it difficult to photograph people and really slows you down as you have to set up a tripod for each shot.
To see whether you can shoot infrared with your digital camera, point a television remote control at the lens, press and hold down the shutter button, and take a picture. If you can see the light in the photo, you can probably take infrared images with an appropriate filter.
If you decide to give infrared photography a proper go, perhaps a better option for you would be to do an infrared conversion of your digital camera which will allow you to photograph infrared images hand held at low ISO speeds and without the need for infrared filters. Since you will no longer need to use an infrared filter in front of the lens it is much easier to change lenses, compose and focus.
You will find interesting exploring Life Pixel which provides digital infrared conversion services, as well as various types of Infrared filters and tutorials for photographers interested in handheld digital infrared photography.
Camera lens filters come either as a circular or square piece of optical glass (often referred to as front or drop-in filters) large enough to cover the lens.
The circular camera lens filters may screw into a thread on the lens rim, providing an air-tight seal when needed for protection. In addition, they cannot accidently move relative to the lens while composing your image.
Their main disadvantage is that they will only work with a specific lens size and today, most of the manufacturers offer lenses that use different size filters. This means that you might end up owning one lens that takes 62mm camera lens filters, another that calls for 67mm add-ons, and a third that takes 72mm accessories. You might find that the best and cheapest way to handle this is to buy the largest filters and then adapt them to other lenses by using step-down rings.
In the case of front camera lens filters, you can fit the lens filter with the use of a filter holder kit. Front camera lens filters are generally more flexible than the circular versions as they can be used on any lens diameter, however can feel more cumbersome to use as they need to be held in front of the lens.
Failing all else, you can also just hold the camera lens filter over the lens.
For most types, it is important to be able to rotate the filter attachment freely because this is the way you alter how the camera lens filter interacts with the image. This means that you can alter the effect for each particular shot.