Today’s Question: When it comes to panoramic photos, why not just crop the scene to a panorama rather than assemble a composite image from multiple captures? Wouldn’t the final image be the same either way?
Tim’s Quick Answer: It is often possible to achieve the same overall composition for a panorama with either cropping or a composite image. However, with a composite image you’ll be able to produce larger output than if you had simple cropped a single photo, which can be especially important if you intend to print the image.
More Detail: Assuming you position the camera at the exact same location, you can achieve the same framing for a panoramic image by using a relatively wide-angle lens for a single frame or a longer focal length lens for a series of images that will be assembled into a composite panorama. There may be some distortion issues involved if you need to use a wide-angle lens for the panorama created by cropping a single image, but the overall framing can be the same.
The key difference, however, is that a composite panorama will have a much higher resolution than a single image cropped to a panorama.
For example, let’s assume a camera with a 24-megapixel image sensor. Assuming an output resolution of 300 pixels per inch (ppi) and an image cropped vertically but not horizontally, you would have a panorama that could be printed with a width of 20 inches without interpolation. Even if you only used three frames to capture a composite panorama, with about 25% overlap between frames, you would still be able to print the composite panorama at a width of 45 inches without interpolation.
If the composite panorama involves more frames, the benefits in terms of output size are even greater. But the point is that with a composite panorama you’re able to achieve much larger output size than would be possible by cropping a single photo.
If you only share your images digitally, or if you don’t need to produce large prints, then you could most certainly achieve the same basic panorama with a single photo that is cropped rather than creating a composite panorama. Just be sure to consider the potential for image distortion if you need to use a wide-angle lens to capture the single frame. For situations where you need to use a particularly short lens focal length to capture the scene in a single frame, you may prefer to create a composite panorama to avoid that distortion, even if you don’t need the larger potential output size.
