10-25-2015 02:42 AM
10-25-2015 07:00 AM
There is no way to zoom lens other than with the lens zoom ring.
The +/- buttons you are refering to are used to increase/decrease the size of an image in playback mode. The +/- buttons are in blue, as is the playback arrow.
10-25-2015 09:54 AM
Also note that when you change the lens focal length (zoom) you will need to refocus -- because for the vast majority of DSLR lenses, the focus changes as you "zoom".