Working with a prime lens rather than a zoom lens requires more creativity when framing. But sometimes, the angle is too narrow. How can you widen it? Merge is the solution, thanks to the use of multiple shots.
Famous photographers like Henri Cartier-Bresson or Alex Webb limit themselves to a fixed focal length, such as a 50mm or a 35mm. By working on composition with a specific field of view, they adopt a certain philosophy: they don’t get distracted by the multiple framing possibilities of a zoom lens, they maintain a certain distance from the subject, they travel with lightweight gear, and so on. While purists refuse to crop, the pragmatists eliminate superfluous and distracting elements at the edges of the frame during post-production.
Focal length too short
But what about situations where the focal length results in a field of view that’s too narrow? Where stepping back isn’t possible? Where the distance from the subject brings unwanted elements into the frame? The solution is to take multiple shots to cover the entire scene, then merge the images together in post-production using software. But a few precautions are necessary.
Plan for the merge
When shooting, a tripod isn’t essential, but the focus must be the same across all images. This is useful both for facilitating the subsequent stitching and for maintaining consistency between sharp and blurred areas. Start by photographing what will be the center of the final composition. The images must overlap sufficiently with one another. To be safe, allow for at least a quarter of the area to overlap between each shot.
The exposure settings (ISO sensitivity, aperture, shutter speed) should preferably be the same, as if they were part of a single shot. A manual exposure mode is therefore more appropriate. The white balance setting, if set to automatic, may vary from one shot to the next: it will be adjusted during post-production.
With six shots, the entire house is captured. The first photo is a frontal view of the building. The others are offset from the first and overlap significantly. The entire field covered by the various shots will make up the final image.
Merging the shots
The shots are merged in Lightroom (or Photoshop or other similar software) by selecting from the Library or Develop module menu Photo > Photo Merge > Panorama… The image merging settings in Lightroom are very effective and offer several stitching projection modes: spherical, cylindrical, and perspective. Spherical projection aligns and modifies the images as if they were mapped onto the surface of a sphere.
This mode is suitable for very wide panoramas. The cylindrical projection stitches the images together as if they were arranged inside a cylinder. While it works well for wide panoramas, keeping vertical lines straight, it curves horizontal lines, just like the spherical projection.
After selecting the photo merge option, if the shots have an exposure difference—even as small as one-third of a f-stop—the selected images may be considered candidates for HDR. Since the goal is not to create an HDR image, click “No” and continue in Simple Panorama mode.
The first available projection mode is the spherical mode. When the subject contains horizontal and vertical lines, the horizontal lines curve and are therefore unsuitable. This mode is best reserved for landscapes. The cylindrical mode exhibits the same type of distortion.
Perspective Projection Mode
These projection modes, spherical and cylindrical, are well suited for landscapes but not for architectural elements, unlike perspective projection, which is based on a flat surface. This mode preserves straight lines but tends to stretch the sides.
Since perspective projection uses the image in the center of the scene to create the blend, care should be taken to ensure this area is well-composed when taking the shot. Finally, if the images include people who do not overlap between shots, they will be retained in the final edit.
Perspective projection is the best blending mode if you want to preserve straight horizontal and vertical lines. It is the preferred choice for blending architectural images. Of course, you can switch between projection modes to choose the most appropriate one. Automatic cropping removes the uneven edges created by the merge (manual cropping in Lightroom is still possible when automatic cropping is not selected). The Boundary Warp option preserves the content of the images.
Discover the professional photography courses at Spéos
Spéos photography school offers professional photography programs in 1 year, in 2 years, short photography programs (in 2 months and in 5 months), as well as photography workshops.
The long courses to become professional photographers allow you not only to master all the photographic techniques and its vocabulary (blurs, hyperfocus, sharpness zone, depth of field, backlighting, focal length, shutter release, autofocus, wide-angle, rule of thirds, etc.), but also all the stages of shooting and image processing.
Visiting the school allows you to discover the premises, the studios and the equipment, and is undoubtedly the best way to familiarize yourself with your future way of working. This is why, in addition to the open days, Spéos offers throughout the year personalized visits by appointment to come and discover the school with a member of the team.
Text and photos: Philippe Bachelier, teacher of Printing techniques at Spéos