Filter basics

By Jack Graham (Jack’s website; his blog; his gallery on this site)

 

Our thanks to Jack for providing this concise primer on using these essential filters – polarizers, solid and variable neutral density filters and graduated neutral density filters. Click on any of Jack’s beautiful images below to enlarge.

 

“My first thought is always of Light”

Galen Rowell

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Filters are a hot topic – sometimes quite controversial. Which is best to use? Which is the best value? And on … and on. Please note the opinions stated in this article are entirely mine. They come from years of experience and observation. I expect to receive a lot of emails with varying opinions, and that’s fine. Please remember these are my opinions. Below I talk about the filters I carry and use the most, though I only use filters when absolutely necessary. Here we go!

 

Before beginning to talk about filters allow me to discuss filter quality. Yes there is a difference. Would you put retread tires on a Lamborghini? Probably not. Why put a low quality $25 filter on a $3,000 lens? It happens more often than not. There is a reason professional photographers use the filters they do and stay far away from others. Think about that when selecting filters for yourselves.

 

Remember these factors when thinking about using filters:

  • Use filters only when necessary

  • Never stack filters on lenses

  • Buy the thinnest filters available. Wide angle lenses need thin filters to reduce any potential vignette

  • Make sure they are clean before each use

  • Understand the benefits and drawbacks of using filters

 There are many filter manufacturers out there. Almost without question, you get what you pay for. But how do you know which manufacturer makes the best filters available? After each category, I’ll give you my recommendation on what to buy.

 

CIRCULAR POLARIZERS

Polarizing filters are the most commonly used filter for any landscape photographer. These filters simply reduce the amount of reflected light passing onto the camera sensor. Just like wearing polarizing sunglasses, polarizers can enhance color, especially in the sky, making the sky a deep blue. These filters also reduce glare and reflections off of water and other bright surfaces. Polarizers also increase color saturation in foliage.

 

Without a Polarizer With a Polarizer
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When rotating these filters and looking through your viewfinder, one can see the variable effect of a polarizing filter. The direction your camera is pointing directly affects the effect of this filter. Polarizing filters work their best at a 180 degree viewpoint from the sun.

 

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A polarizer was used here to remove some glare and enhance the color

 

Be careful. Even without these filters on our wide angle lens, skies can be uneven when not at 180 degrees. Using a polarizing filter will enhance this unnatural look making the image unbalanced and unrealistic. In the image below the sky is darker on the left than on the right. I did not need to polarize this image.

 

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Sometimes we want the color reflected on or below water to be viewable. Polarizing filters counteract this and can reduce the color and reflection. Be careful and analytical when using these filters.

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A polarizer used in this image would remove much of the color of the rocks beneath the surface and leave the water dark and drab.

 

Your light can be reduced up to 2 or sometimes 3 stops. Handholding with slow shutter speeds can be a problem when using polarizing filters.

 

Never use a non-circular polarizer. Though less expensive, these non-circular filters affect metering and autofocus, making them useless.

 

BENEFITS: Reduces glare on water and foliage; Darkens skies; Enhances color.

 

DRAWBACKS: Can remove color off water; Uneven darkening if not used correctly; Can decrease light by 2-3 stops.

 

RECOMMENDATION: The best available is SINGH-RAY or B+W; SCHNEIDER is the next best; High end (brass ring) HOYA next tier but good; Tiffen, Cokin and all others are last choice.

 

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I almost always use a polarizer when there is a lot of green foliage.

 

NEUTRAL DENSITY FILTERS

 

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Above is a 96 second exposure using Singh-Ray’s 10 Stop Mor-Slo ND FILTER

 

Neutral Density Filters, often called NDs, reduce the amount of light reaching the camera’s sensor and therefore increase the length of the opening of the shutter. These filters are used most often when photographing long exposures and when your ISO is at its lowest setting. Attaining smooth, silky water and using blur to convey motion are the two most common reasons for using these filters. These filters will allow you to use a shallow depth of field in very bright light. (For information on making long exposures, please read this article.)

 

These filters, more than others, can add a colorcast to the image when they are used. Some are better than others. Singh Rays are the best I have found. Singh Ray makes NDs in 5, 10, and 15 stops as well as a 2-8 stop Variable ND. For water you do not need more than a few seconds, if even that, to get the best shot. That’s where the Variable ND comes in handy.

 

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4 seconds using Singh Ray’s Vari ND filter

 

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Singh-Ray’s Vari ND

 

BENEFITS: Increases exposure time; Great for long exposures on water and moving clouds.

 

DRAWBACKS: Good understanding on usage necessary; Color shift when using low quality ND’s.

 

RECOMMENDATION: SINGH-RAY is the best available, hands down. Most others I’ve seen have lots of color shift.

 

BELOW—LEE BIG STOPPER BELOW—SINGH RAY 10 STOP MOR SLO ND
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GRADUATED NEUTRAL DENSITY FILTERS

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I used a 3 stop Soft graduated ND to make this image

 

First … avoid the screw-in type filters. They do not allow you to move the filters transition line!

 

Cameras are limited in recording what we call ‘dynamic range’. Often, either the darker areas of the scene will be underexposed, or the brighter parts will be overexposed. Graduated ND filters are clear on the bottom and slightly darker, depending on the strength, on the top, with either an abrupt or a gradual shift in the middle. They are used to darken the brighter part of a scene so it appears natural taking into account the dynamic range of the camera.

 

These filters are made to equalize light from overly light areas to normal or even dark areas. They are commonly sold in increments of 2, 3, or 4 stops. They gradually, from top to bottom, start out at their darkest and blend into clear. Though one could take 2 images and blend them together, getting it right with a GND is my choice. When combining images often noise is introduced into the image. Also when the light is changing fast, blending images can produce some interesting but unwelcomed effects. A good article talking about using these filters can be found HERE

 

It is important to select the proper GND for each scene. I rarely use hard edge GND’s.

 

Soft Edge grad Hard Edge Grad
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NO GRAD FILTER  3 STOP SOFT GND

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Learning to place the blend in the proper location takes some practice. I suggest using a tripod and a filter holder to increase your precision.

 

BENEFITS: Equalizes light.

 

DRAWBACKS: Using too strong a filter when it’s not needed can make the image look unnatural; Inexpensive filters tend not to have the proper gradation (blending).

 

RECOMMENDATION: Once again, SINGH-RAY is the best available, hands down; LEE is a distant second; New version Cokins are better than before but still third choice; Most other brands I’ve seen have lots of color shift.

 

Hope this was helpful!

 

All Photographs as well as text appearing here are the property of Jack Graham and Jack Graham Photography LLC, unless otherwise noted.