If you do use a mobile phone then if on a tripod or secured another way do use the Timer function for shutter release.
It will eliminate camera shake.
Timer function also is a work around on a digital camera if no remote app is available.
Our own Digital Cameras are a good few years old and we have a wired remote shutter release which is what I use for digitising images of large or bulky items that do not fit on a scanner.
