I suggested this tag wiki for digital-photography:
Digital photography clearly is the bulk of picture-taking today; this tag doesn't need to be on everything that is digital, but can be used when the question is specifically about the technology involved.
and it was rejected by one of the moderators.
If you look at the use of this tag, it's pretty random. Most questions which deal with digital cameras and digital photography don't use the tag, but some do rather arbitrarily. In this sense, it's one of those too-broad-to-be-useful tags — like putting "camera" on everything. But in other cases, where the question really is about digital technology or process, it seems quite appropriate.