What is a Filter and Do They Still Matter?

December 17, 2015  •  Leave a Comment



What is a filter and why do photographers use them?  The most basic answer is a filter is a photographic tool that alters, color temperature, lighting, or creates special effects when taking photos.  Filters are primarily used for outdoor photography, though there are occasions when they are used indoors. They are placed on either the front of the lens or in a slot in the rear of the lens.  There are two types of filters, circular which is screwed on to the front of your lens or rectangular which is either placed in a filter holder which is also screwed into the front of the lens or in the rear slot in your lens. So in a world of digital cameras, computers, and photoshop are filters still necessary?  The answer is a resounding yes.  These are the filters I think every photographer should still be using.

The first filter is a polarizing filters.  There are two types of polarizing filter, linear and circular.  For the modern dslr you must use a circular polarizer other wise your autofocus will not work.  What is a polarizing filter?  In short the filter cuts down glare and haze while increasing contrast.  It is particulary good at making clouds in the sky pop and taking reflections out of glass.  If you are shooting landscapes or buildings outside you should definitely have a polarizer on your camera most of the time.  Remember when you use a  polarizer the filter will cut your exposer by about a stop and a half.  So if your exposer is 1/120 at f 16, you must adjust your exposer to 1/120 at f 11 with the filter on because the filter cuts the amount of light that passes through the lens.  

The next type of filter you should have is a graduated neutral density filter.  A graduated neutral density filter has a neutral density filter on top to cut the amount of light coming in and is clear on the bottom.  They come in various strengths from one stop to three stops.  These filters are very important for landscape photographers but benefits everyone.   The reason you need these filters is that as photographers we are taught to photograph scenes with clouds because it's more interesting.  But big puffy clouds on a bright sunny day act like diffusers and reduce the amount of light reaching the ground.  So what happens is the clouds are brighter then the scene you are shooting so whether you use an incident meter or a reflective meter your subject will be exposed properly but the sky will be washed out and have no definition.  To solve this you use a graduated neutral density filter.  To properly use this filter you must first take two exposers one of the clouds and one of the subject on the ground.  The difference between the two tells you the strength of the filter you need to use.  So if you expose the clouds at f22 and the subject at f11 then you know it is a two stop difference, so you need to use a two stop graduated neutral density filter.  Line up the top half of the filter with the sky and shoot your subject at f11, your subject and sky will now have the same exposer.  

The final filter you should have is a variable neutral density filter.  The main difference between this filter and a graduated neutral density is that there isn't a a clear bottom.  A variable neutral density filter is great because you can dial in how strong the effect you want.  In the past photographers would have to carry four or five neutral density filters each in a different strength.  Now this one filter does the work of all five.  This filter is a great creative tool because it is specifically designed to cut the light that reaches the sensor.  By reducing the light, it allows you to use slower shutter speeds even in full sunlight.  As an example if you're photographing a waterfall at golden hour and your exposure is 1/125 of a second at f16.  You have the perfect light but you want the creamy effect of running water which you can't get with your current shutter speed.  This is where the neutral density filter comes in.  You can use the filter to lower the shutter speed three stops.  So now your exposure is 1/15 of a second at f16.  So now you have the perfect golden light and the creamy effect of running water.  One PSA for all new photographers, when using this filter you should always be using a good tripod and a cable release.  I don't not recommend attempting to hand hold the camera.  

Are there any filters you should use if you're taking pictures inside?  When photographing inside filters are not really neccessary because most indoor filters were designed to correct color temperture but modern dslrs can adjust their white balance to correct these issues without a filter.  As an example when everyone used film a common indoor filter was the FL-D which was used when photographing in a building with flourescent lights.  When you used film if you didn't use the FL-D your photos would have an ugly green tint because florescent bulbs have a color temperture of about 4200K and film had a temperature of 5700K.  In modern cameras the FL-D isn't necessary because you can just change your white balance to florescent.  Even that isn't always necessary because the auto white balance is actually pretty good.  I do use a diffusing filter to soften the image and cut contrast.  These filters come in many names, I use the Tiffen black mist pro which comes in varying strengths.  Basically these filters soften the skin tones while maintaining sharpness.  If digital has a flaw it is when you photograph people it is too sharp and every blemish, wrinkle, and scar jumps out.  These filters lessen that effect.  Whether you use this filter is a personal choice, some people like it, some don't.  

And there you have it the filters every photographer should have and use.  Filters are a great tool, that will enhance your photography, so I hope you will give them a try.  





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Christopher Eng-Wong Photography is a commericial stock studio. We sell digital graphic art prints here on our website and stock photos through Shutterstock, Bigstock, Dreamstime, and Fotolia. Thank you for visiting our blog.
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