TIME and MOTION Cooperate to Produce Unique Photographs of the Ocean's Power

Pebble Beach, San Mateo County, California -- March 17, 2007
by Mike Collette, founder of Better Light, Inc.

Because of the time required to capture each high-resolution image, scanning backs are usually not considered for photographing moving subjects, but these unique image recording devices can produce equally distinctive results with certain kinds of subject motion.  For example, I have seen several beautiful examples of ocean surf photographed by Better Light owners, but I didn’t have any examples of my own that I could share with everybody.

When pro photographer Robert Leslie (www.leslieimage.com) contacted us recently expressing interest in seeing how a Better Light scanning back would interpret moving subjects, I invited him to join me for a trip to the ocean to try a few experiments.  Also joining us was Mark Liebman, the founder and president of Pictopia (www.pictopia.com), who became interested in our experiments after a conversation with Robert.  We met at Better Light’s facility in San Carlos, and traveled about 30 miles to nearby Pebble Beach to take scanning photographs of the Pacific Ocean. 

Although it was bright and sunny in San Carlos, a layer of low clouds provided welcome diffusion when we arrived at the coast.  However, the gray clouds also made for rather gray water, as can be seen in this picture of Robert (left) and Mark with the equipment.  Mark is holding my lightweight laptop to prevent it from being blown off the backpack by the constant wind off the ocean, which also made setting up and focusing the camera more interesting, as shown in the photo below.
photo by Mike Collette, Better Light
photo by Mark Liebman, Pictopia
Fortunately, an extremely low tide minimized any wind-driven spray and allowed us to set up right at the edge of a rock outcropping overlooking the water, high enough to get a great view.  My Ebony SV45U2 field camera proved to be quite stable in the wind, even when using a 450mm lens, thanks in large part to the sturdy platform provided by a Gitzo G1548 carbon-fiber tripod and G1321 leveling head. 

I knew that our images of the moving waves would be affected by the lens focal length (image magnification), the scanning back’s exposure setting (scan speed), and by the orientation of the scanning back in the camera, which would establish the scan direction relative to the direction of the waves.  To minimize the variables for our brief visit, I kept the scanning back’s exposure setting at 1/240 second per line for all images, for a constant 35 second full-resolution scan time.  I captured images with three different scanning back orientations using a 135mm lens, then switched to a 450mm focal length and made another series of images. 
Here is a “normal” instant-capture image of the ocean made with a compact digital camera and a telephoto lens setting.  Because of the rather low scene contrast, ALL of these images of the ocean have had their contrast boosted significantly for a much clearer rendition.  However, even the enhanced contrast didn’t bring out much color in our subject, as evidenced by this full-color (?) photograph.  
photo by Robert Leslie
Our rather monochromatic subject meant that motion artifacts caused by the moving waves would be the predominant source of color in the scanning back images.  There is a slight delay in the time that each color channel gets recorded for each line of the image, and if the subject moves during this time, it will appear in a slightly different location in each color channel.  Continuous subject movement therefore causes the color channels to appear slightly out of registration, and this misregistration among colors creates colored artifacts, particularly along high-contrast edges.

Alternatively, the almost-colorless subject also meant that I could choose a single color channel to make black and white photographs without losing much from the original scene.  Using a single color channel eliminates any misregistration for a much sharper result.  Unless otherwise noted, the following examples use only the green channel of the original color images from the scanning back to make black and white photographs.

Here is the same scene captured with the scanning back and a 135mm lens.  This is only a small section of the overall scanning back image, cropped and sized to match the instant-capture photo. 

The scan direction in this image was from left to right, which was approximately THE SAME as the direction of the waves.  This combination of focal length (scene magnification), exposure time (scan speed), and scanning back orientation produced a situation where the waves were moving across the image at approximately the same speed as the image sensor, producing long, drawn-out wave crests. 

Rotating the scanning back 180 degrees in the camera reverses the scan direction across the scene, for a considerably different result.  The scan direction in this image is from right to left, so the image sensor is now moving AGAINST the direction of the waves.  The distant waves look fairly conventional in this instance, but the waves closer to the camera, which appear to move faster than the distant waves, look somewhat squeezed.

Putting the scanning back in the camera vertically causes the scan direction to proceed from the TOP DOWN across the scene.  Instead of capturing vertical “time slices” across the image as in the previous examples, the scene is now recorded as a series of horizontal “time slices”. 

This isn’t quite the same view as the others because the vertical subject framing cut off the leftmost part of the scene, but the scale and distance are similar so the results are still representative of what one might expect from these conditions.  Distant waves are captured quite quickly across the entire scene, for a fairly normal appearance, while closer features don’t look quite right. 

Switching to a longer lens focal length -- 450mm instead of 135mm -- causes the waves to appear to move across the image over three times faster than before, thanks to increased scene magnification.  The following examples from the scanning back were again cropped and sized to match the instant-capture image.  Now things really start to get interesting…

Even though the scan direction is approximately THE SAME as the wave motion in this example (scanned left to right), the much faster wave movement now causes many crests to catch up and pass the image sensor as it traverses the scene.  This (subject moving faster than the image sensor in the same direction) causes the moving subject to appear reversed in the recorded image, as is evident here.

Rotating the scanning back 180 degrees in the camera again causes the scan direction to be AGAINST the direction of the waves.  Combined with the increased scene magnification from the longer lens focal length, the rapid movement of the subject across the image sensor reduces any misregistration among color channels, and the resulting colored motion artifacts. 

This particular example is the full-color image data, with no attempt to reduce or eliminate any motion artifacts.  You can see hints of extraneous color, particularly along high-contrast edges, in this reduced-resolution example.  Sometimes this “added” coloration works with the subject to produce an interesting result, although in a large print the image misregistration becomes more apparent, and a single-channel black and white photograph may still be preferable for its improved sharpness.

The image scanned TOP DOWN with the 450mm lens does not look appreciably different than the TOP DOWN image made with the 135mm lens, since in both cases the (different) speed of the moving waves had little influence on the resulting images.  This is once again a slightly different view caused by the narrower image width of our vertical subject framing. 
Below are full-resolution black and white samples from the scans done with the 450mm lens.  The first is from the image scanned in THE SAME direction as the moving waves, while the second is from the image scanned AGAINST the direction of the waves.  Each vertical line of pixels in these examples was exposed for 1/240 of a second, with adjacent lines exposed sequentially -- left to right in the first example, or right to left in the second.  The short exposure for each line effectively “freezes” the water at that location, and the smooth sequential exposure provided by Better Light scanning backs produces smooth contours of the surging water, for a unique photographic interpretation not possible with any other method.  Each of these 800 x 600 pixel examples represents one percent of the entire 8000 x 6000 pixel originals -- click the Zoomify links to examine the rest.
FIRST IMAGE – Same direction as waves.
Click here to view full resolution Zoomify image
SECOND IMAGE – Against direction of the waves.
Click here to view full resolution Zoomify image
photo by Robert Leslie
photo by Robert Leslie

After making a total of seven photographs of the ocean in about twenty minutes, we packed up and moved to another part of the beach to try out the Better Light Pano/WideView™ adapter.  In this case, the ocean was a somewhat distant part of the scene, with strangely shaped sedimentary rocks holding a number of freshly-filled tide pools occupying most of the image.  The photo above shows the entire setup, and to the right is a close-up of the camera with the Pano/WideView adapter under the camera.

Note that for this photograph, the lens has been shifted down as far as it can go, and the rear of the camera has been raised about two centimeters.  As a result, the optical axis of the 135mm lens is actually below the image area, and the camera is looking down into the scene without tilting.  This view camera technique also applies to panoramic images, where it is important to maintain a cylindrical view of the subject as the camera is rotated.  Positioning the center of the lens over the axis of rotation, as shown, minimizes parallax errors during panoramic scans.

Above is the resulting panoramic image, encompassing about 105 degrees of horizontal view.  This 378 megapixel, completely uninterpolated digital image was scanned in just 90 seconds using a Better Light model 6000-HS with the Pano/WideView adapter.  Click the Zoomify link below to examine the full-resolution image. 
PEBBLE BEACH PANORAMA
Click here to view full resolution Zoomify image

Return to Top of Page