Filter Types… What can filters do to enhance your image?
Technically this is not a filter since it doesn’t do anything to change the light or colour but it does provide some essential benefits. Using a clear filter on your lens will help protect it from scratches, fingerprints, and dust. If by chance you happen to drop the lens, the filter should offer the camera lens some measure of protection. For an inexpensive piece of glass, you could be saving a lot of repair costs.
Clear (aka Protection) Filters »
UV or Ultra-Violet
One step up from the clear filter is the UV or Ultra-Violet filter. While ultraviolet light is invisible to the human eye, it can nevertheless show up on a film image as an undesirable blueish cast; it can even result in a blurring effect. Often used as a means of protection for the film and digital lenses, these filters can be left on at all times as it is completely clear and will not change the colour or density of light. Ideal for photography of expansive spaces like mountains and sweeping landscapes.
UV (Ultra-Violet) Filters »
Neutral Density (ND)
A popular filter for outdoor photography, these filters are neutral grey and reduce the amount of light passing through the lens . Used to prevent overexposure or washed out images when the light is too bright or the ISO is too high; it also allows you to lower the intensity of light so you can shoot at a slower shutter speed and achieve a blurring affect. Not only does it correct exposure but at a wider aperture it reduces depth of field enabling the foreground to maintain sharpness and blurs the background for a pleasing effect.
Often refered to as “ND” filters, neutral density filters are available in varying densities allowing you to control your filtering depending on the light conditions.
Neutral Density (ND) Filters »
Colour Conversion or Correction
All film has a colour balance (or temperature) to suit a particular set of lighting conditions. Daylight film is designed to yield correct colour for photographs taken under daylight conditions. Tungsten film is designed to yield correct colour under warmer tungsten light – the light of ordinary household light bulbs. Sometimes you may not have the right film in your camera for the lighting conditions you’re shooting in. That’s where colour correction filters come in.
They can eliminate unwanted colour casts and ensure your image renders colour accurately. Colour correction or conversion filters belong to two groups; orange and blue. The orange CC filters “warm up” scenes that were too blue, and the blue CC filters “cool down” the scenes that were too orange or red. Each filter in each group varies in strength; they’re very precise in how much they shift colour. This colour cast and strength is expressed in degrees Kelvin. For example, the daylight balance or colour temperature of daylight film is 5200 degrees Kelvin. (The higher the number, the bluer the colour, the lower the number, the warmer.) Currently colour conversion or correction filters are used predominately on cameras that use film.
They also can be used on digital cameras that have automatic white balance and no manual option. Digital cameras with manual colour temperature selection can be set internally to match the colour of the scene and thus no external colour correction filters are required.
These filters are cyan, magenta and yellow in colour and they absorb different amounts of the red, green and blue parts of the light spectrum. As a result, they correct deficiencies in the colour quantity of light sources. They also reduce unwanted rays or intrusive reflections.
Colour Compensating »
Reflections of water and other reflective surfaces, like glass, can cause major problems for your images. Polarizing or polarized filters can fix them because they remove glare from non-metallic surfaces, ensuring a crisp, clear, more colour saturated image.
Reflected light can also wash out an image, but polarizing filters combat this nicely by producing deeper colour saturation.
Ideal for outdoor photography, a polarizing filter can be rotated for desired effects and the results will produce dramatic blue skies and better contrast and colour.
Polarizers comes in two types: circular and linear. Circular polarizers are used predominantly in autofocus SLRs/DSLRs so as not to interfere with the exposure metering and autofocus system.
Polarizing Filter »
Circular Polarizing Filter »
A classic filter used for portraits or subjects that require a dreamy or haze appearance. Diffusion filters reduce contrast and softens the image in varying degrees depending on the manufacturer’s type. Also known as a softening filter, the more subtle varieties are ideal for portraits as it softens imperfections from skin without blurring out features like the eyes.
Diffuser Filters »
What happens if the image you are capturing only needs a filter on only one part of the scene? Graduated filters are half clear and half coloured allowing you to position the filter so that only a part of your image is affected.
They are available in neutral density and colour varieties in screw in or drop in filters. Drop in filters are typically a little bit longer in size so you can position the transition of the filter in a specific spot. The transition between the coloured half and the clear half can be soft or hard.
Graduated Filters »
To add dazzle and glamour to your night scenes, star effect filters take points of bright light and turns them into star shapes. These shapes streak from the source of light and the brighter it is, the more enhanced it becomes. Some of these filters can be rotated giving you complete control over your creativity.
Star Filters »
Common accessories for screw in round filters are step up or step down rings. These ring adapters allows you to use a filter size that does not match the size of your lens. For example if you have 52mm lens and want to purchase a 67mm filter, you could use a 52mm-67mm step up ring to accommodate the difference. This same idea applies to step down rings but in reverse. Stepping rings allow you to use on filter on two different-sized lenses and avoid the need to buy a separate set of filters for every size of lens you own.
Stepping Rings »