The "depth of field" of a safari binocular refers to its ability to keep objects further towards the background and closer towards the foreground in focus without you having to adjust the focus. Stated in another way: Once you've focused on an object in the distance, how far behind this object (in other words, further away into the background) and how far in front of the object (in other words, closer to you, the viewer) is still in focus, without you having to adjust the focus. Even yet another way: Once you've focused on an object some distance away, how far will this object remain in focus if it either moves further away from you, or closer towards you. This is what is meant by the "depth of field" (DOF) of your safari binocular. The DOF also changes the closer the object you're focusing on, decreasing the closer you get.

Few people ever think about this when considering buying a binocular and they are seldom informed about this. Generally speaking, the higher the magnification (power) of your binocular, the shorter the depth of field - yet another reason why you should not fall into the trap of going for as high as magnification as possible, as some uninformed people tend to do. A safari binocular with magnification of 8x is close to ideal. A binocular with a very high magnification will have virtually no depth of field at all, which means that only the object you're focusing on will be in focus. These type of binoculars can only be operated from a tripod, since the high magnification makes viewing very difficult in any case: Small movements by the viewer are magnified. Even the slightest motions like normal hand tremors associated with holding binoculars up to your eyes ("binocular shakes") become a huge problem. On top of this, you're stuck with a considerably smaller field of view as well.

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