To Infinity ... and Beyond?
Hyperfocal focusing can be confusing in part because of the varying explanations that can be found of the concept. Let's test your ability to spot the ones that are right and those that aren't.
First, as a refresher, I need to make sure my readers know what hyperfocal focusing is intended to do. We can then move on to how to achieve it. Within the limits of its design and manufacturing, a camera lens can be set to be focused at any given distance. That then becomes the only distance at which things will truly be in focus. But there's a range of distances, both in front of and behind that distance, where things will appear to be in focus. They actually won't be, but they'll be close enough to being in focus that we can't tell that they aren't. And that's what matters. If things look to be in focus, then we'll be happy as photographer, and anyone looking at our images will be happy too. Depth of field depends on many factors, but it's never limitless. Hyperfocal focusing deals with maximizing depth of field so as to cover objects far away from the camera and as many of those nearer the camera as possible.
All that sounds pretty good, but the devil is in the details. If you ask a dozen photographers how to achieve hyperfocal focusing, at least some won't have a clue. But of those who think they do, only some will be right. So, with that in mind, I present here a self-test to see which group you are in. Don't worry, nobody else needs to how you do. This is all just to help you master the concept of hyperfocal focusing. I'm going to list some various statements that could be used to teach hyperfocal focusing. See if you can pick out the ones that are correct from those that aren't.
Start counting backwards from infinity. The number you are at when you fall asleep is the hyperfocal distance.
No, you're thinking of "hypnosis," not "hyperfocal". And while photos taken after you have been hypnotized might be embarrassing, they won't necessarily have any greater depth of field than those shot while you aren't mesmerized under someone's spell.
Let your eyes go crossed. The point where they are then focused is the hyperfocal distance.
Again, this one is wrong. Focusing on the end of your nose so your eyes go crossed may make you the center of attraction at your next social outing, but it won't do much for improving the depth of field in your images.
Right now, poised at the edge of the galaxy, Emperor Zurg has been secretly building a weapon with the destructive capacity to annihilate an entire planet! I alone have information that reveals this weapon's only weakness.
Oops. That's a quote from Disney's Toy Story. It has nothing to do with hyperfocal focusing.
Hyperfocal focusing is just a fancy term for focusing your camera lens at infinity.
Most lenses have markings on them showing the distance they are focused. Such markings invariably use the "sideways eight" symbol for infinity to indicate setting the focus point as far away as possible. For all practical purposes, the horizon is at infinity, so if you want to take a picture of something like a mountain that is effectively at the horizon, you can set your lens to focus on infinity. This will have the added benefit of having a vast range of distance in front of the horizon appear to be in focus. Even though the lens is actually focused at the horizon, the depth of field will extend for quite a way in front of that mountain, making things in that range appear acceptably sharp too. But that depth of field would theoretically also extend beyond the horizon, stretching "beyond infinity," as it were, where nothing actually exists. As such, focusing on infinity wastes a good portion of your potential depth of field since nothing exists beyond infinity. Nothing is beyond infinity.
Hyperfocal focusing is a myth. Albert Einstein proved that it doesn't exist.
No, he proved you can't go faster than the speed of light, but didn't really say much about focusing at infinity or anything similar.
The hyperfocal distance is the closest distance at which a lens can be focused while keeping objects at infinity acceptably sharp.
This definition is from Wikipedia so hopefully it is correct. Indeed, with the lens focused at this mythical distance, the depth of field will span from somewhere between us and that focus point all the way out to infinity, but not beyond. Unlike in earlier flawed attempts at defining the concept, the focus will be pulled back such that the portion previously wasted beyond infinity will just barely touch the horizon. At the same time, the closest distance at which things will look acceptably sharp will also be pulled closer, giving us more depth of field. Indeed, this is the most depth of field possible, and thus we are at the hyperfocal distance. If we focus any further away, some of our depth of field will lap over beyond infinity. If we focus any closer, our depth of field won't be able to stretch all the way to infinity. So yes, this definition is correct, but it doesn't help us much to put all this into practice. Using this, the only way to determine the hyperfocal distance would be to look it up in a table or use a software program to determine it for us.
The hyperfocal distance is the distance from the camera lens to the closest object that is in focus when the lens is focused at infinity.
This one is also correct and, while still somewhat confusing sounding, is actually the most workable definition I know of. To understand how to put this definition into practice, think of hyperfocal focusing as a two-step process. First, Focus your lens on infinity. No, don't keep it there. The portion of your depth of field in front of your focus point will seem great, but you would be wasting the other half of your possible depth of field by letting it fall beyond infinity. Instead, with your lens focused at infinity, make note of the closest object that is in focus, and then refocus your lens to that point. By doing so, your entire depth of field will be shifted closer such that the portion previously beyond infinity will now span from this new focus point to end just at infinity, and the usable portion that previously ended at infinity will now fall in front of the new focus point. This makes the entire theoretical depth of field usable, giving us the maximum possible, without need to look anything up on a hyperfocal focusing table or make use of any other other external aid.
See, that wasn't so hard, now was it?