As shown above, on the back of your camera, press the ‘START/STOP’ button while the camera is in photo mode (switch upright). This will activate the live view mode whereby you can see on the LCD screen what you would see through the view finder. Once you have this view you can press the magnification button on the left hand side of the back of your camera. This preview is of the Canon 7D mkii and may vary depending on the make and model of camera you use.
Doing so will allow you to zoom in on your frame without having to zoom your lens and alter your focal point. Pressing this button more than once will allow you to zoom even further. Once you are zoomed in on your furthest subject, you can use manual focusing on your lens to ensure that that furthest point is in focus. you can then press the magnification button again to zoom back out, or exit live view mode and take your image to review. Below are a couple of landscape photographs that I had taken in this manner.
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