Pass: rainer
As I have learnt the hard way, LCD's are useless in bright sunlight. While some digital cameras also  have optical viewfinders these tend to be rather inaccurate i.e. they show less of the actual picture and they suffer from parallax, which gets worse the closer the object is.
Here is a simple solution to that problem using  the body (with lens) of a 35mm slide viewer.
Transform your digital camera LCD into a pseudo thru-the-lens viewfinder

The modified (by drilling three holes and removing one side) housing of on old AC adapter with a magnifying lens glued to its top (lens focal length aproximately 3...5 cm)  replaces the slide viewer that was used in the design above.
Now one has access to all control buttons of the camera without having to remove the viewer.
Improved Versions
Here is Sony DSC P10  with a less bulky viewer canibalized  from  an old Exacta camera and modified for viewing the LCD
Viewer closed
Viewer in operating position