The characteristics of Large format camera
The distinctive characteristic of large format camera is, at the first a large film area obviously, and it’s capability to tilt and shift front plate and back plate to manipulate the image plane.
Stitching multiple photos has the effect increasing the sensor area as shown below. It will multiply not only the pixel counts but also angle of view as if a wider angle lens used. For example, in full-frame camera, 85mm lens works as a mild telephoto, but it is a standard lens in a medium format camera. Further, it becomes a wide-angle lens in 4X5 camera and ultra-wide-angle lens in 8X10 camera.
It does not matter whether we take single shot with a large format camera OR take several shots with smaller format and stitch them to create a large size photo, the formula works exactly the same way.
Panorama vs Stitching
Adobe uses the term ‘panorama’ rather than the ‘stitching’ in Photoshop menu. Therefore when you perform ‘photo stitching’, you actually select the panorama menu and work on it. But it generates some confusion. Merge multiple photos to one big chunk is not always panorama.
A panorama photo means a picture in long and narrow frame either side-to-side or top-to-bottom. It is possible to create a panorama with single shot photo by cropping as well as by merging photos together. Stitching, on the other hand, does mean merging photos together no matter it is long & narrow or square or whatever shapes… Stitching is proper term to explain this function even though Adobe doesn’t think so…
// This reminds me an old glitches from Nikon. They used the wrong term ‘micro-‘ prefix for the macro lens to confuse people, so Nikon’s micro-Nikkor is not the microscope lens at all. It is the macro lens actually. Micro- lens normally means the lens equipped in microscope and Macro- lens means a camera lens which is capable to focus very close distance, to reproduction ratio 1:1. I don’t know why and how this confusion occurred in Nikon, but nevertheless they like to say a ‘deer’ as a ‘horse’ until now…. //
Increase the number of pixels and angle of view
The stitching technique is more useful for landscape photography than portrait in terms of finer detail generation. For example, instead of 24mm wide angle lens, use 50mm lens to cover ¼ of the scene and merge them to make the same photo as 24mm shot later. This way, sensor area is increased 4 times and pixels too. And it will preserve 4 times more details than single shot photo.
Tilting focal plane
In Portrait photo, it is more useful to tilt focal plan to get sharp image along the main subject.
In normal camera like full frame or even medium format, when focus to 1 point, front and back area become blur progressively, or close aperture down to smallest opening will extend DOF further front and back. But in this case, not only main subject but also background become sharp which distract viewer’s attention from the main subject (e.g. people). That’s why portraits often taken with large aperture lens in wide open to emphasize people with blurry background.
The front tilt of a large format camera slants the focal plane as shown in diagram. It makes the surfaces of main subject sharp while maintaining very shallow DoF to blur background. In the case of multiple photo stitching, we can focus to the area 1, 2, or 3 separately, so that make very similar effect to the front tilt of large format camera.
Back to very first example photo, three individual photos focused on center area (1, 2, and 3) while the depth of focus maintained shallow because I used the 85mm lens with f2.0 aperture setting. The merged photograph is also focused on face, arms, and knees (1, 2, and 3), while background & floor are out of focus.
If this photo taken in single shot, I have to close down aperture to f11 or f16 to make (1, 2, and 3) area sharp, then not only model but background & floor become all the way sharp. Or I may focus the lens focused onto model’s eye with wide open, and accept the arms and knees blurred significantly, simply because no other choice with normal camera…
Cautions when take background photo
It is entirely photographer’s decision whether focus to multiple surfaces, or focus one place and keep the rest of shots blurry. In latter case, it is less likely fail to stitch photos. Stitching problem happens when try to merge sharp image with blurry image. If both images are blurry or sharp, it will not be a problem.
I practiced with 2 configurations so far:
- Leica M9-P, 50mm f0.95 lens set to f1.1 : with this setup, I did not adjust focus after first shot (model’s head shot). Merged photo looks virtually the same as single shot except bigger pixel count & sensor area. It did not fail stitching work at all.
- Sony A7R II, 85mm f1.4 & 55mm f1.2 : with this setting, I used AF function so focus adjusted each shot. Sometimes fail to merge photos as explained in this article
Another important matter is when shoot background, need to avoid entirely blurry image. Photoshop needs some details to determine where to stitch, therefore it will fail if only bokeh and color smearing are in the background without any details.
Panorama-Stitching is very useful technique when super details needed, shoot in confined place, take wider shot with an available lens and mimic large format camera. It works well for static subject, landscape, architecture and portrait in controlled environment. But it will not work for dynamic situations like street photo, snap shots or candid photos.