Understanding Polarizing Filters and Natural Density Filters

There are many kinds of filters to help you control the light in a scene when capturing the shot. Two very common and useful filters are polarizers and natural density filters. We previously explained how polarizers can affect an image and here we will explain the difference between linear and circular types. Also, the usefulness of natural density filters will be further expounded upon.

circular filter Understanding Polarizing Filters and Natural Density FiltersLinear vs. Circular Polarizing Filters:

Circular polarizing filters are designed for metering and auto focusing functions of a camera. Usually, if the camera is equipped with autofocus, a circular polarizer is what is most advised.  Most modern cameras are equipped with a polarizing half mirror known as a split beam metering system. In most cases, a circular polarizer is needed for the meter to be accurate.

Linear polarizers are less expensive but cannot be utilized for cameras with through-the-lens (TTL) metering and auto focus, which encompasses most of the models of digital SLR cameras. You can make do without metering and auto focus, but these are sure fire ways to help improve your images.

Light rays reflecting from any surface are already polarized. Polarizing filters selects what kinds of rays are allowed into your camera’s lens. Linear polarizing (PL) and filterpolar3 Understanding Polarizing Filters and Natural Density FiltersCircular polarizing (CIR) filters do the same, but it’s important to know what best suits your camera. This permits you to filter out any undesirable reflections from surfaces that are non-metallic such as glass and water. It also allows color saturation and makes hues more vivid with improved contrast without affecting the color balance of an image as a whole.

Neutral Density (ND) filters:

ND filters function by lessening the light that reaches the camera’s sensor. This is most helpful when long exposures are not possible in a range of apertures that are set at the lowest ISO setting.

These may best be applicable in scenarios where you need to smooth out a shot when trying to capture images that include flowing water such as rivers, waterfalls and oceans. ND filters can help you attain a shallower depth of field in bright light situations. It also helps reduce diffraction which also reduces sharpness by allowing a larger aperture to make subjects in motion appear less defined, allowing blur to indicate movement.

ND filters are best applicable when trying to diminish light. Now light can be reduced by using faster shutter speeds, or using a smaller aperture which will impact depth of field. However, by using an ND filter, it allows you to reduce light without compromising your exposure settings. You can have a slower shutter speed or a larger lens opening without fear that the shot will be overexposed. 

The table below is a guide on attaining the correct amount of light required in a shot using the different ND filters based on the general information already provided by relevant companies:

filter chart Understanding Polarizing Filters and Natural Density Filters

Just a couple of ND filters are needed to achieve extreme light reduction to allow long exposures in broad daylight and a few f-stops for subjects in motion.


Share |

Submit a Photography Article!

Posted in Articles, Cameras and Equipment, Miscellaneous
Tags: , , ,

No Comments »
Print This Post Email This Post
Permalink | Posted in Articles, Cameras and Equipment, Miscellaneous
Understanding the Various Camera Lens Filters

A camera lens filter is an accessory that allows photographers to have more control over the images they capture. These filters can either be round or square in shape, made of glass or plastic, and can either be screwed or clipped in place in front of the lens. Although, filter effects can be copied in common editing software techniques, actual filters will give much better results and some are very difficult to reproduce. Here are some popular filter types with their various uses and advantages that can help you create better images.

Filter Types:

filter2 Understanding the Various Camera Lens FiltersLinear and circular polarizers – these filters reduce glare and boost saturation. Usually used in landscape photography where skies, greenery, and water are the main subjects.

Neutral Density (ND) filters – this is often colorless or gray in shade and modifies the intensity of all wavelengths or colors of light in equal measure, while leaving the color hues intact. With an ND filter, you have more options to play with the exposure settings. For example, if you want to have a motion blur effect of a waterfall and there is bright sunlight, you can use this filter instead of decreasing aperture size (to lessen the amount of light entering the sensor). This means you do not have to sacrifice depth of field to capture the image.

Graduated Neutral Density (GND) filters – this is great for lessening the possibility of vignetting and helps control light gradients. This kind of filter is divided into a darker side and a lighter side and the division in the middle, which blends these two shades, varies from soft to hard. This is often used for landscapes that show a dramatic change in lighting, such as a bright sky above a dark row of trees.

filter3 Understanding the Various Camera Lens FiltersUV/Haze – a very useful all-around filter and protects the lens as well. This was often used with film cameras to cut the atmospheric haze that could be captured in the image. Since digital cameras are much less sensitive to UV rays, this filter serves the purpose of general protection of the lens.

Cooling/Warming filters – these filters are used to alter the white balance of the scene. They have cool or warm colored tints. Ideal for underwater images, landscape shots and images that make use of special lighting.

filter7 polar1 Understanding the Various Camera Lens FiltersPolarizers or polarizing filter – this enhances landscape images by cutting down on the intensity of reflected light that goes through to the camera’s sensor. Much like polarized sunglasses, it makes the sky and water seem a deeper blue, and makes the trees and other plants, and even rocks a more vibrant color saturation that increases the visual appeal of images.. It reduces glare and reflections from water and other reflective surfaces as well as decreases the contrasts between the skies and the ground.

As advantageous as polarizing filters can be, be careful because it can also greatly diminish the amount of light that reaches your camera’s sensor by at least 2 to3 f-stops, which is about ¼ to 1/8 amount of light. You might need to compensate for this by using a slower shutter speed or using a bigger lens opening.  Moreover, using polarizers in wide angled lenses may create unbalanced or skies that look visibly darker than usual.


Share |

Submit a Photography Article!

Posted in Articles, Cameras and Equipment, Miscellaneous
Tags: , , , , ,

No Comments »
Print This Post Email This Post
Permalink | Posted in Articles, Cameras and Equipment, Miscellaneous