Friday, February 27, 2009

An introduction to ND filters and graduated ND filters -- and what's the difference?

Since we work with filters every day, and deal with so many experienced photographers, we sometimes forget that not all of our readers and customers are familiar with the basics of Solid ND (neutral density) and Graduated ND filters.

Apart from being a noted outdoor photographer and author, Rod Barbee is also a workshop instructor and is aware of the confusion some photographers experience when it comes to selecting and using Solid ND and Graduated ND filters, so we asked Rod to review the basics.

"At one of last year’s workshops," says Rod, "a client wanted to learn to use her new 'ND' filter. She'd been told that she needed a 'neutral density filter' to control the contrast in her landscape pictures. When asked which filter she had, she pulled out her brand new 'solid' neutral density filter. Oops. What she really needed to get was a graduated neutral density filter.

"If this sounds like it could happen to you, don’t feel bad. Confusing the terms solid ND filter and graduated ND filter actually happens with some regularity -- even among experienced photographers. Many people, workshop instructors included, refer to graduated ND filters simply as 'ND filters.' So when someone relatively new to outdoor photography is told they need to get a “2-stop neutral density filter” to control bright skies, they dutifully order a 2-stop solid neutral density filter. Ouch.

"OK, what is the big difference, you ask? Read on….

"Many solid neutral density (ND) filters are mounted in threaded rings just like many other optical filters so they can be quickly and easily mounted on the front of our lenses. They are dark grey in appearance and come in several different 'densities' that reduce the amount of light passing through the lens by a specific amount (from 1-stop up to 5-stops or more). The word 'neutral' in neutral density is important because it indicates the filter is completely neutral in terms of its color -- meaning it won’t affect the natural color of anything in your scene. . .so the blue sky stays blue, the grass stays green, and the yellow roses stay yellow."

Editor's Note: Singh-Ray offers the 5-stop Mor-Slo Neutral Density Filter in a ring mount (above), as well as our rectangular George Lepp Solid ND Filters in 1, 2, 3, 4 or 5-stop density to fit the Cokin P-size or Z-Pro filter holders.

"Now let's discuss what you can do with solid ND filters. Their purpose is to cut down the amount of light reaching your film or digital sensor -- which lets you keep your shutter open for as long as 30 seconds or more in broad daylight. Some uses for longer shutter speeds include blurring water in streams, waterfalls, and various moving subjects. You may also want to slow your shutter speed in order to stretch moving clouds across a sky, creating various zoom effects, and blurring the action of objects moving around a still object. In the photo of the seagull (above), I used an ND filter to achieve a one-second exposure which added some motion blur to the water.

"You can also use neutral density filters to control the amount of light needed to shoot at a specific aperture and shutter speed, as I did for this tulips-in-the-rain image (actually, tulips with a watering can). First decide on the aperture you need to get the pleasing blurred background you want and then choose a specific shutter speed that will show some motion in your moving subject. When the existing light level is too much to give you exactly that exposure, you can place an ND filter on the lens that will reduce the amount of light to a level that lets you use your predetermined exposure settings. Let's say you want f/4 at 1/8th second but at f/4, your camera gives you a shutter speed of 1/125th. Since you’re probably using your lowest ISO setting already, the only solution is to cut the amount of light entering the camera. A neutral density filter can do this (in this case, 4 stops of ND are needed).

"There are many creative things you can do with a set of neutral density filters. The photograph of a fishing boat in Newport Harbor on the Oregon coast was made by zooming the lens during a long exposure achieved by adding a neutral density filter. But you don’t need to buy a whole array of ND filters with various densities since Singh-Ray developed the variable ND filter that offers any density you need from 2-2/3 to 8 additional f-stops of density. Singh-Ray’s Vari-ND is my go-to filter whenever I want to get creative with my shutter speeds.

"Now let's briefly talk about the purpose of graduated neutral density filters (also often called 'ND Grads'). These are the contrast controlling filters used to reduce the transmission of light in only a part of an image -- such as the bright sky in a landscape. Professional quality graduated ND filters are flat, rectangular filters that are half clear and half dark. When properly positioned in front of your lens, the gradient area blocks just enough light from the overly bright areas in the scene to bring the light levels in the scene into a range our film or digital sensor can record. Many of the most dramatic scenes in nature involve a bright, beautiful dramatic sky at sunrise or sunset coupled with a compelling foreground. Often the range of light in a scene like this is beyond the ability of the film or sensor to capture all by itself. That’s where a Graduated ND filter comes in.

"This pair of photos of Lake McDonald in Glacier National Park shows the subtle but important difference an ND grad can make. The shot at left was made without any filter, and the shot at right was made with a Singh-Ray 3-stop soft-edge Graduated ND filter. As you can see, my Graduated ND filter allowed my camera to capture the full tonal range in the scene that would otherwise not be possible. (Click the image to enlarge the comparison.)

"Both Solid ND filters and Graduated ND filters from Singh-Ray may take a little practice to use, but once you start using them, you’ll never leave them out of your camera bag. In my book, they're essential to every landscape photographer's success."

To check out what else Rod has to teach you, visit his website at www.rodbarbee.com to learn more about his upcoming workshops and ongoing writings.

Tuesday, February 24, 2009

Vari-N-Duo and 3-stop ND Grad capture the total magic of Death Valley before the storm

Although Brian Rueb got hooked on photography while in college, he says, "Once I was married and my kids started arriving, my photo bug all but vanished. Then came the digital SLR... and while the initial investment was big, there was no more buying $7 rolls of film or paying $8 processing fees to look at a bunch of images I didn't like. I got hooked again.

"In the past three years, I have been shooting more and more regularly. I still find, however, that photographing new places is a special challenge. I roll into a location hoping all the research done before departure will pay off and I'll be in the right places at the right times. Even when I am, the weather also has to cooperate. In the case of a recent last-minute trip to Death Valley National Park with fellow photographer Stephen Oachs, we had done the research, seen the storms in the forecast, and decided to roll the dice.

"With our crock pot cooking a pork roast in the car, we drove the 10 hours from San Jose to Death Valley National Park. On the way we discussed priorities for shooting locations and came up with our list: Mesquite Dunes, Badwater Basin, Devil’s Cornfield, the Racetrack and Zabriskie Point.

"Weather is such a key component to any good landscape shot. I'm almost always toying with a storm -- hoping to get to our location right before the storm, or right after. Of course I also hope, if we end up in the middle, that the storm won't be too lengthy. In this case, there was heavy rain in the forecast for Death Valley, so we knew the storm was a doozy.

"It was 82 degrees, sunny, and warm when we reached the valley floor…we could see the storm lingering on the horizon….waiting to descend. A brief stop to set up camp in Furnace Creek and we were off to shoot.

"Our first evening’s shoot was in the Badwater Basin (photo above), and by the time sunset was drawing near the storm had dropped into the valley. Our light and composition possibilities were fading quickly. Badwater Basin is a perfect spot to use Singh-Ray filters. The ground is very light, and with the dark storm approaching, I needed to balance out the scene. A Singh-Ray 3-stop soft-step Graduated ND filter worked perfectly. I combined it with the Singh Ray Vari-N-Duo filter so I could use its built-in LB Warming Polarizer to really warm up the ground and create some separation between the storm and sunset. If I had wanted to streak the sky, and create that sense of movement, the Vari-n-Duo’s ND filter would’ve allowed me a wide range of exposure options as well. I hand hold all my ND Grad filters and move them on longer exposures to help eliminate any shadowing the filter might cause. I’ve used a lot of other filters in my time and the Singh-Ray filters give me the truest and most accurate color and the highest level of control over my subject. This allows me to present an image almost exactly as it appeared when I was there. With the successful Badwater Basin shoot to brag about, we made an evening out of eating the pork roast.

"Our plans for the next morning would depend on the weather. If we woke to a windless, star-speckled sky we would head to the Mesquite Dunes, but if it was windy, we would head to Zabriskie Point to avoid geting caught in a sand storm out on the dunes. Sand storms are very tough on equipment.

"The morning was beautiful and perfectly calm. We drove to the dunes and hiked out to a more remote section to await the sunrise. Every so often the universe lines up perfectly for an amazing photo opportunity. This was just such a case. This is also when having the security of Singh-Ray filters pays off. Using the Vari-N-Duo and 3-stop soft-step ND Grad combination, I was able to dial in just the perfect amount of polarization to bring out the warmth of the sunlit dunes and not lose any of the amazing storm clouds that were starting to fill the valley. Without using filters, capturing a scene like this, with such harsh light would be nearly impossible. And because of the storm there were no other photographers in the dunes. It was pristine and amazing.

"With the morning shoot at Mesquite Dunes completed, we spent the rest of the day scouting locations and figuring out where to set up for our evening shoot. Death Valley truly is a landscape photographer's paradise. It’s quite overwhelming. The options are limitless as to where you can shoot and when the weather is as dramatic as it was during our visit, it’s simply stunning.

"For the evening shoot, we decided on the Devil’s Golf Course, a fiendish maze of salt crystals and mineral deposits that winds its way throughout the Death Valley floor. While we’d been fortunate to dodge the storm for the majority of the past two days, our luck was beginning to run out and the storm was really moving in. We were dodging rain drops as we set up our equipment. I chose a section of the valley where the clouds were breaking apart, and dramatic light was filtering through, illuminating the peaks in the background. I used the same combination of filters that I used for the other shots. I find that the polarizer in the Vari-N-Duo really helps the color and separation in cloud structures -- especially in such stormy conditions. The filter really helped those clouds above the peaks to stand out. The filter also gave the scene that other-worldly 'Lord of the Rings' feel, which was exactly how it felt to me standing there photographing it.

"When I first got into landscape photography, scenes like this would’ve overwhelmed me. I would’ve inevitably botched the entire shoot, coming home with only partially correct exposures. Using Singh-Ray filters has allowed me to capture the scenes I see as perfectly as I could have ever hoped. I have the type of color and exposure control in the field that would’ve taken me hours in Photoshop to duplicate. Now when I leave a shoot, I’m excited to go home and see the images on the big screen -- without dreading all the post-processing I would have to do.

"That shoot at the Devil’s Golf Course turned out to be the last one of the trip because the storm came in hard and heavy that night -- chasing us out at first light and ultimately washing out nearly every road in the valley. But for our day and a half it was total magic."

You can find more examples of Brian's photography on his website and his Flickr portfolio.