How to adjust the zoom and focus of the Pro-780 camera

The zoom and focus controls are located on the rear of the camera.

ZOOM: The left hand dial controls the level of zoom. You can vary the viewing angle between 35° and 70°. This is an approximately 2x optical zoom, which operates in a similar manner to the

zoom on your digital camera. Basically, zooming in makes everything appear to be larger, at the expense of the viewing area. Check out the diagram to the left for a visual representation of the zooming process. The smaller viewing angle (marked 35°) represents the camera’s view when “zoomed in”, and the larger angle (70°) represents the camera’s view when “zoomed out”. You can set the zoom to either of these extremities, or anywhere in between. When you change the zoom, you’ll also have to change the focus. Why? Lenses are complicated, and all the bits are joined together. Changing the zoom will also change the focus.

 

FOCUS: The right hand dial controls the focus. Adjusting the focus control is kind of like trying

on a different pair of glasses - it can make sharp things look blurry and blurry things look sharp. It’s not quite magic, but it’s pretty close. Basically, once you’ve set the zoom, twist the focus knob until what you want to see doesn’t look blurry anymore. If you can’t turn the knob any more one way, go back the other. You can only have so much in focus at once - photographers refer to the size of the area in focus as the “depth of field”. The diagram to the right shows a couple of different focusing options. The shaded areas represent the depth of field. As you can see, there is no hard edge, some things are “more” in focus than others. Note that this is for illustrative purposes only - there are many factors which contribute to depth of field which vary from location to location.

A: The lens is at its widest, and focused on an area relatively close to the camera. The depth of

field is quite large.

B: The lens at its widest with focus set to “infinity”. Anything in the shaded section will be in focus, and this focus extends to infinity (that is, things in the far distance will also be in focus). However, things in the distance might be too small to see the detail you require.

C: The lens at its tightest, focused on an area close to the camera. As you can see, the more

the lens is zoomed, the smaller the depth of field becomes.

D: The lens at its tightest with focus further from the camera. At this distance, the actual depth

of field is much larger, but it doesn’t extend to infinity like it does when the lens is wide.