Today’s Question: When shooting for panoramas, is there a maximum number of individual photos to include? I got this message: “Unable to merge photos, not enough matching photos for merging”. I had 25 individual photos to merge. Was this too many?
Tim’s Quick Answer: There isn’t really a limit to how many photos can be merged into a composite panorama, other than limitations related to maximum pixel dimensions, file size, and memory available when assembling that panorama. In this case the issue you’re running into is likely that the content of the photos is not distinct enough for the software to accurately combine the photos.
More Detail: When capturing the individual frames for a composite panorama, each frame must be overlapped to some degree (generally around 20% to 50% depending on the lens focal length and other circumstances). That overlap enables software to look for similar features from one frame to the next, so the images can be blended together into the final panorama.
With a typical landscape panorama the software is generally able to find matching features among the overlapping areas of each pair of photos, enabling the composite image to be assembled with relative ease. However, if there are not distinct features across the full scene you’ve photographed, it can be difficult (or impossible) for the software to merge the images.
For example, I recently captured a composite panorama that included a boat at the far left end of the scene, with nothing but water across the rest of the scene. While there was certainly a considerable amount of texture in the water and sky that represented most of the scene I was photographing, there weren’t enough distinct features that could be aligned, since the waves would have changed from one frame to the next. As a result, I couldn’t find any software that could assemble that particular panorama.
It is still possible to assemble such a panorama with a manual approach, such as by using layers and masks in Photoshop. That can still be a challenge, of course, but when you are exercising direct control over the layer masks that are being used to blend the images together, you can find ways to blend them that will work for the final result.
As noted above, assembling a composite panorama that consists of a large number of photos generally won’t be a problem. Many applications are limited in terms of the total pixel dimensions that can be used for any image, and overall file size will be limited depending on the specific hardware and software configuration. But other than these types of limitations, you can assemble composite panoramas with a large number of individual frames, including individual frames that represent multiple rows of captures for the same scene.