No more split-graduated ND filters

For a landscape photographer, one must learn how to deal with the great variations in exposure value between the sky and the foreground. In the film industry, it has been called "sky control", although one may want to control the foreground as well. Generally, the sky ends up being much brighter than the foreground, and the disparity between the two, although within the range of the human eye, can't be handled by conventional film/digital sensors. So, what to do about this?

In the old days of film, I used the photography standard "Split-graduated neutral density filters". Essentially, they are thin pieces of glass or resin, that have a graduated pattern that blocks out light in varying stops (degrees of exposure value). They are clear in one half, and dark on the other. They come in different stop values with different degrees of gradients-usually described as hard or soft edge. You pick the right one for the specific scene and slide it down over the end of your lens and it makes the foreground and the sky the same exposure value.

I really disliked using those filters! First of all, they are not truly neutral in my opinion, they are difficult to get lined up correctly, they scratch and get fingerprinted easily, if it is raining, get out the umbrellas!, and finally, you are adding layers of stuff on the end of expensive, high quality glass, inevitably causing some quality compromise. Well, welcome to the digital world! I got rid of nearly my entire filter collection, including the Split ND's a long time ago. But what is the approach now? Below is an example of what/how I approach this issue today, using a digital camera, RAW files, and photoshop gradient filters.

Multiple Exposures using Photoshop's gradient filter

It was a dark morning with mostly cloudy skies. The thin clear area in the east looked promising for a splash of sunshine, so I quickly found a place that might work for a daybreak landscape. The tundra was in its prime crimson color, and I knew the warmth of it would explode at first light. When the sun is rising over a horizon with quickly moving clouds, there is little time to waste. In this scene, I knew that I needed to balance the exposure using two or more frames--one exposed for the sky and one for the foreground, so I set the camera to a 3 set auto-bracket sequence of 1-2/3 stop increments (that's about 5 stops total) I set the self timer to a 2 second delay, (I was on very soft tundra, not the best for stability). Once the sun appeared I shot a test shot and looked at the exposures, made sure the histograms looked o.k. for each scene. Oh by the way, being in manual exposure mode is a must.

There is however and additional issue that arises: Lens flare. I used a 24-105mm zoom lens for this shot, and zoom lenses are pretty well known in general for flare, since there are so many internal glass elements for light to bounce off of. I own 5 lenses in the 24mm range, which is ridiculous, but they all seem to have a purpose. I did not however have my little 24mm prime, which would have handled the flare much better. So, what is my work around? Well, it's a little more time consuming, but pretty simple. For one frame, I just hold my finger over the sun so it reduces the flare on the bottom half of the image. Depending on the situation, you might need to reverse this for the sky image as well. What would be handy is a little articulating arm on the tripod that had a small dodge tool on the end of it, and one could bend it in place. But then, it's likely I'd forget that occasionally anyway! I always have my fingers, and working fast is the critical issue.

Exposure for the foreground, using my finger over the sun to block out the unwanted flare otherwise evident (see image below).

Exposure compensating for the bright light of the sky.

So, I have the two frames: 1) Foreground- with my finger in the sky over the light source to block the flare exposed for the foreground. 2) Sky. Open the files in Lightroom to make your adjustments to the raw file, then open the two in photoshop. Pick one image, drag it into the other while holding down the shift key and it aligns it perfectly (presuming your tripod did not move). Then apply a gradient filter using a mask, which emulates the old split graduated ND filter--but with much more control. This whole process can be done rather quickly.

Final blended image using two photos and photoshop's gradient filter to emulate the former split graduated neutral density filter.

Yes, it is true that if you used the real Split grad ND filters, you would have an original file that is balanced. While that is a nice thought, I go for the former for reasons of simplicity, quality, and control. Welcome to the digital age. Get rid of the split grads!

Digital Composites

Nowadays, digital composites are everywhere. While editorial images should be honest and unmodified, there seems to be no limit with advertising and promotional works. We received a recent example of this when we got our copy of a Russian calendar featuring some of our polar bear photos.


Our photo as it appears in a Russian polar bear calendar


The original photo

I like what they've done by adding a horizon, which breaks up the white-on-white of the photo, and also adds some blue which goes well with the off-white of the polar bears. Take a closer look, and you'll see they also added catch lights to the eyes. When naturally occurring, these are a desirable and attractive element in photography. They add a sparkle to the eye and bring attention to it. However, it has to be believable when added digitally. Catch lights usually indicate a light source, so there should be some shadows in the photo, and this one was taken under overcast skies. They are also pretty extreme in the cubs eyes on top, and perhaps would be more pleasing toned down some.

An interesting thing about catch lights is they are often used to determine if a photo is faked. Sometimes it is obvious, if for example different people or animals in a photo have catch lights in different positions of their eye, or some are missing, etc. In some cases, advanced software is even used to calculate light sources and angles when it is critical to determine if a photo is legitimate.

We sometimes create digital composites and post them on our web site if we think some creative modifications can be made. When we do, we are sure to make a clear statement in the photo caption information, and confirm with the client that it's OK before completing a sale.

Here are two examples:


This totem is not really a composite because it originates from only one file, but so much "digital lighting" is done that we list it as a digitally modified image.


This photo was created from several photos for a request for a commercial fishing boat in a clearing storm. The original boat was photographed on a sunny day, and several layers of mountains, clouds, and rain were added.

High Dynamic Range: HDR

One advantage of shooting digitally is the higher dynamic range compared to slide film. This allows greater shadow and highlight detail, bringing photography one step closer to what the eye is capable of seeing.

Sometimes, however, it's still not enough. When this is the case, one option is to create an HDR, or High Dynamic Range photo. HDR can also be used to create unique effects, but this example is geared more towards making difficult scenes look more vibrant and real than the camera can do alone.

Shooting for HDR requires some foresight; you must shoot several frames of the same scene. Generally, 5 frames is enough. More can help, but the frames must line up perfectly, so fewer can be beneficial. Since the frames must align, subjects in motion are usually not an option. Even a light breeze can cause problems with trees. With the camera on a solid tripod, preferably using mirror lockup and auto-bracketing, shoot five frames no more than one stop apart. Exposure changes must be made with the shutter, or else the depth of field will change between photos.

Here are three photos from a series of five. The middle one looks OK, but is a little dark, under-saturated, and has some overexposed areas. The lightest image reveals all the shadow detail, and the darkest image will be used for the highlight detail from the sun.


Using the Merge to HDR command in Adobe Photoshop CS3, we blend the five images. First we apply adjustments to the camera raw images, but we don't convert them to Tiffs. The raw images have more data. Merge to HDR outputs a 32 bit image, which has over two billion levels per color channel, compared to just 256. This allows the file to have more detail than a screen can display. Normally, pure white or black areas in a photo are just that, but with the HDR image, if there was detail in one of the original files, these deep shadows or blown highlights can be adjusted to bring out the detail.

The real trick is to show all of these details at once for display or printing. After changing to the more usable 8- or 16-bit mode, the HDR conversion dialog appears. This is where the final look of the image is determined. There are several conversion methods which work for different images. The best thing to do is simply experiment. Many photos seem to benefit from "Local Adaptation," as in this example. This also lets you dial in a curves adjustment to optimize contrast at the same time. The final result is a photo that reveals the glowing, pastel colors of this frosty morning.

Aurora borealis in the White Mountains, Fairbanks

I have long looked for a scene that embodied the mystery of the aurora in conjunction with the simplicity of wilderness living. This cabin, under a sky of wheeling and whirling color, needs little commentary. I accessed this location with a friend, and we both drove snow machines.

While offloading my machine from the trailer, it failed to start. My friend and I removed the exhaust system and began troubleshooting the dilemma in the cold, and an hour later we were fortunately able to start it up. We scurried down the trail, reaching the cabin just before dark.

A little bit of light in the western sky contributes the light blue color in this image. There was no computer color saturation performed on this photo, but colors revealed on film are often different than what the eye actually sees.

Temperatures dipped to minus 18 degrees F that night. This happens to be the first frame I took. While I like many of the other frames, this one, with the lightness of the sky and the purple lights, is my favorite.

Sharpening for printed output

When printing from a digital source, sharpening is required for the most pleasing output. The technique we use may be familiar to anyone who uses Photoshop, but the degree to which we sharpen is often surprising. What you see on the screen is not what you see in printed media.

This is the original file, sized down and sharpened for screen viewing

Here is a 100% crop, unsharpened

Sharpened using Photoshop smart sharpen, 132%, radius 2.0 pixels

The crop sharpened for print output looks oversharpened. It almost looks cut out, with a sort of halo around the edges, when viewed at 100% as shown here. However, all of these artifacts disappear when printed. Part of the reason is most current monitors show around 100 pixels per inch, or ppi. This is like viewing under a 3X magnifying glass compared to printed output.

Photoshop: Replace Color

One challenge with indoor photography is shooting under mixed lighting conditions. The camera, whether digital or film, tends to pick up color variations in light sources with a much more dramatic effect than is noticeable with the human eye. If there is just one light source, the photo can be white balanced to correct for any color cast. However, if there are multiple light sources, the photo can only be balanced for one type, and parts of the photo acquire a strong color cast.

In this example, The subjects were front lit with a tungsten balanced strobe, but top lit with very green mercury vapor lamps. Photoshops replace color command under the image/adjustments menu does a fine job at shifting the hue of just one color in a photo.

Note the green cast in the hair on the before photo at left.

Lightroom Marathon

A desire to maximize the quality of photos on the website prompted a marathon endeavor of re-processing and fine-tuning nearly all of our RAW format digital files. This was no simple task, and it occupied the office for weeks. Our tool of choice for this process is Adobe Photoshop Lightroom. It offers the fine control we need to really get the most out of the RAW file format our cameras output.

Lightrooms "Develop" Tab is where we perfect many of our images.

Mt. Augustine Volcano

Mount Augustine volcano, Cook Inlet, Alaska.

Stitched panorama photo made with two images. It was selected for the ATT Alascom Calendar for 2007.

March 14, 2006 brought clear skies to southcentral Alaska, and I ventured to Homer to attempt some photography of Mt. Augustine volcano for a book project. I was aware of the volcano activity but really have to thank a friend and colleague Calvin Hall, who had sent me some inspirational images of the volcano he had taken the previous week. From a roadside lookout just outside of Homer, you can see the volcano on a clear day, approximately 75 miles away. I waited until the sun had set and the ambient light dropped low enough to let the "lava" or technically called "incandescence" glow with the help of a long exposure. You could not really see it with the naked eye. I've learned from my dusk to dawn photography experience that you can end up with unusual visual discoveries when looking at images made with lengthy exposures. This is particularly true with the Aurora borealis.

Long exposures with a telephoto lens require extreme tripod stability to prevent camera movement blur. I used a 500mm lens with a 1.4x converter (equivalent of 700mm) on a sturdy Gitzo tripod with a RRS panorama swivel ballhead. After taking the first frame and checking the histogram very carefully, I swung the camera to the left for the second frame allowing about 1/3 to 1/2 overlap. The exposure time was 95 seconds for the first frame and 102 seconds, for the second one (I added a little more time to compensate for the slightly darkening sky). With a total exposure time for the scene at about four minutes, there was not much time for experimenting. Throw in a test shot or two before hand, and timing becomes critical. You can see more photos of the volcano on my site: Mt. Augustine volcano photos

Mount Augustine volcano, Cook Inlet, Alaska, March 14, 2006, 7:34PM
Canon 1Ds Mark II, 500mm f4.0L IS, with 1.4x, 95 sec @ f5.6, ISO 400
Frame 1 of 2

Mount Augustine volcano, Cook Inlet, Alaska, March 14, 2006, 7:36PM

Canon 1Ds Mark II, 500mm f4.0L IS, with 1.4x, 102 sec @ f5.6, ISO 400
Frame 2 of 2

Panorama stitched from two images.