Depth of field and hyperfocal focusing.

Banff, Alberta - Shot from the Lake Louise gondola.

Depth of field is a simple concept; it is the amount in focus in a photograph.  What affects depth of field is totally different.  There are a host of variables.  Hyperfocal focusing uses the knowledge of those factors to manipulate the camera and its lens to get a picture where everything is in focus.  This is especially tricky if the "everything" includes parts of the scene only a foot or two away from your shooting position. 

The parameters affecting depth of field are listed below.  Each one includes a thought on how to manipulate it in such a way as to achieve hyperfocal focus.

1)  Aperture - Depth of field varies directly with a lens' aperture.  Low f/values such as f/2.8 provide less depth of field than higher f/numbers such as f/22.  You are more likely going to be successful if you use a smaller aperture, especially if it is near or at its maximum value.  The above photo was at f/13.

2)  Focal length - Depth of field varies indirectly with focal length.  A wide angle lens, say a 24 mm relative focal length has much more depth of field at the same aperture than a telephoto lens, say 80 mm.  When trying to do hyperfocal focusing, consider using a wide angle lens, or even an ultra-wide angle lens.  The above photo was shot using a 20 mm lens on a full frame camera.

3)  Point of focus - If you were to focus at a spot 6 feet away, the depth of field would go out away from the camera in both directions from that point.  Depth of field has a distance before and after the point of focus.  When doing hyperfocal shots, the camera's lens needs to be focused at a point before the lens hits the infinity distance marking on it.  This can be done using focus locking, manual focus, or overriding the autofocus using the lens' manual override feature if present.  Focus too far away and you lose depth of field in front of you; focus too close and you lose it for the far distance.  The exact point can be determined using software, but I prefer to pick a focus point and check the image later for sharpness.  This is done pressing the play button and zooming in using the magnifier button.

4)  Sensor size - Smaller sensors give better depth of field values than larger sensors using the same relative focal lengths and apertures.  This is because a lower actual focal length is required to give the same field of view on a larger sensor camera.  Even though the smaller sensor requires greater enlargement, it still ends up having more depth of field overall.  This is why it is difficult to get out-of-focus backgrounds on compact or cell phone cameras, regardless of the lens settings.

5)  Amount of enlargement - If you take any image and look at it as a thumbnail, it will all seem in focus.  Enlarge it a bit and parts of it will likely start to look blurry.  Enlarge it some more and the trend will continue.  When doing hyperfocal photos, try to use the entire frame rather than cropping the image, as more enlargement will cause the overall depth of field to decrease.  An image may look sharp as a 5x7 but have blurry areas as an 8x10 or 16x20.

6)  Closest object - consider keeping some distance between the camera and the closest object to be in focus.  Getting hyperfocal focus is likely going to be more successful if your closest object is 3 feet away and not 6 inches.

If you follow these steps you will find your success rates with achieving hyperfocal images will improve.  Practice and play, check and verify, shoot and learn.  But most of all, have fun.