[RETOUCHING] Creating Digital Panoramic Photos

Dec 30, 2011

Over the last 14 sections, we have discussed digital photo retouching from the basic principle to the composition of digital photos. In this section, we will first look at some of the completed digital works, and follow a simple step-by-step guide with some useful tips.

Oct 28, 2010

Over the last 14 sections, we have discussed digital photo retouching from the basic principle to the composition of digital photos. Digital photo retouching can span from simply removing unnecessary parts to introducing imaginary or nonexistent elements into the photograph using multiple layers and channels, and so infinitely expanding its boundaries.
Digital photo retouching can be either easy or hard, depending on your intentions and ability. In this section, we will first look at some of the completed digital works, and follow a simple step-by-step guide with some useful tips.
■ Text and picture by Sim Hyun-Jun (studioSUM President, SunChon National University Department of Photographic Art Instructor)

▲주상복합-Park, Jin Myung

▲panorama landscape-stock photo

A panoramic photo is a photograph specifically shot to include a wide landscape. Prior to the introduction of the digital camera, panoramic images, which are mainly used to shoot vast landscapes and which are by no means easy to capture on 3:2 or 4:3 films, were shot using special panoramic cameras. Most panoramic cameras were expensive and difficult to acquire unless you were a professional photographer specializingin panoramic photographs. (Even today, panoramic cameras are still very expensive.) To create a panoramic photo, you had to shoot with a 5×4 camera equipped with a 12×6 holder using a 120mm film, or simply shoot with a 5×4 film in wide angle and trim the top and bottom to give a panoramic impression.

▲digital panorama - Sim, Hyun Jun

Since digital photos became popular, it has become easier for everyone to create a panoramic photo using a digital camera and some basic Photoshop skills. Of course you could always use a wide-angle lens on a high-pixel digital camera to shoot a wide angle photograph and trim the top and bottom, but if you don’t have a wide-angle lens or a camera with high pixel resolution, you can always put several photos together to create a panoramic photograph. This is called stitching. Photoshop has a feature called Photomerge which can automatically stitch several photos, which is very handy when it comes to creating a panoramic photo.

▲Photo A: Panoramic photo of Cheongdam Bridge

Photo A shows a panoramic photo of the Cheongdam Bridge. These days, the bridges on the Han River are well illuminated and make for splendid nighttime scenery. Recently, water fountains were added at each end of the Banpo Bridge, creating a beautiful view..

▲Photo B: The original photos

The three original photographs in Photo B were shot to create the panoramic photo. These photographs were shot in 1.5:1 ratio crop body, with a 17-35mm lens. ISO 100, aperture f11, and shutter speed 15s. I could have used two landscape photos, but the maximum width range was approximately 25mm due to the crop body (converted from 35mm film camera), even with a 17-35mm wide-angle zoom lens, so it was difficult to include the buildings on the other side of the bridge. I also wanted a higher resolution photo. Three portrait photos would certainly yield a higher resolution than two landscape photos.

▲Original photos within a large format document

To create a panoramic photo from several photos, there are a few things you need to consider: First, selecting an appropriate tripod and head. The photos to stitch must have the same lens axis, that is, their centres must be identical, and absolutely steady with no shaking. In short, you will require a strong tripod with soft and precise panning.
Especially for nightscape photos like Photo A, which are shot with long aperture, even a slight instability might dramatically affect the quality of the image.
The second thing to pay attention is the distance between each photo.
To effectively stitch the photos, each photo must have some sections overlapping with the adjacent ones. This may depend on the lens you will be using, but in general it is suggested that you shoot each photo with 15 to 20% overlapping sections. It is also preferable to use a lens which doesn't have a distortion toward the edge. I would suggest using a normal lens or a telephoto lens. If you use a wide-angle lens, the edge of the image will be severely distorted, and you will have difficulty stitching the photos due to the distortion in the overlapping sections.

To create a panoramic photo, you can either put each photo together in Photoshop manually, or use the Photoshop's Photomerge tool to automatically stitch the photos. First, let's look at the manual option. Open the original image in Photoshop, check its size, and create a document larger than the three photos aligned side by side. Drag the original images to the newly created document in appropriate order. Positioning the layer according to the image order would also make things a little easier. When you've finished positioning the images, the next step is the most important part: putting them together. Although they are shot with overlapping sections, these sections do not exactly correspond with each other. Even if with a telephoto lens, which has no perspective distortion, the images will not overlap with exact precision. This is primarily due to the slight distortion toward the edge of the lens.

▼Displaying the Grid

To resolve, use the Distort tool in the Transform menu to adjust the distortion of the image so that the overlapping sections can fit together. To make things easier, I suggest you turn on the Grid and the Guide Line to show the horizontal and vertical grids. (View>Show>Grid)

▼Putting the images together

When you've finished putting the photos together, adjust the brightness of each image. Even if you use the same aperture, shooting photos at night inevitably results in a slightly different aperture for each shot. Therefore, it is necessary to adjust the aperture of each image (select one photo as the base aperture) with the Level or Curve tool. If you adjust the brightness of the image, adjusting the adjacent sections might also brighten or darken the opposite sections.

▼Adjusting the brightness of adjacent sections

Again, this is due to the insufficient light at the edge of the lens.
To resolve this, apply a masking to each layer and use a brush to correct the distortion and brightness together by carefully removing the overlapping areas.

When you've finished adjusting the distortion and brightness, you'll see that the outer area of the panoramic image is now uneven.
Use the Crop tool to cut the image to the desired size. Cutting the image wider will make it more panoramic.

▼Crop

It's almost done. Retouch the imperfect areas and adjust the overall colour. Nightscape photos are generally amazing but when magnified, there may be some notches like unlit street lamps or neon signs. These notches are likely to disrupt the light pattern, so it's better to take a close look and fill them in. Next, look at the overall image and adjust the water surface and buildings that appear too dark; finally, burn the outer perimeter of the image so that it appears as a single photo.

▼Partial editing

▼Burning the outer perimeter

You can also convert the colour or crop to a different size to create another photo.

▼A wide crop

▼Black/White conversion

So far, we've learned how to put the photos together in Photoshop manually. This is a very precise task producing a high-quality output, but if the images don’t fit together, it may become quite difficult to cut and stitch each section with another. In Photoshop, there's a feature called Photomerge which helps complete this task more easily.

▼Photomerge

The Photomerge tool automatically detects the intersection of two adjacent images and put them together using appropriate methods such as Auto, Perspective or Cylindrical, and creates a smooth tone between the two adjacent sections.
The Interactive Layout also enables a more precise correction.
The best solution to create a panoramic photo is, therefore, to use the Photomerge command to put the images together, and make necessary corrections manually for a perfect photograph.