By definition hyperfocal distance is:
“The distance between a camera lens and the closest object that is in focus when the lens is focused at infinity.”
Yeah right…but what does that even mean? …Well here is a more accurate definition:
“The hyperfocal distance is the point of focus where everything from half that distance to infinity falls within the depth of field.”
Yeah, that’s better but…
What is it used for?
I wonder if you have ever seen one of those National Geographic magazines in which every landscape photo is sharp from the foreground all the way to the background. That amount of depth of field is useful for landscape photography. Have you ever wanted to take a shot like that? If the answer is yes then you should know that it is not that complicated.
Just follow these steps:
- Set you lens to the minimum aperture (highest F number)
- Set your focus to the corresponding hyperfocal distance
- Take the shot
Simple right? After doing this you will get a shot with the greatest depth of field possible.
How does it work?
If I set focus at the hyperfocal distance (H) the depth of field will go from half that distance (H/2) to infinity (∞), if I set the focus to H/2 the depth of field will go from H/3 to H, and so on. Following this logic I created a table to better understand it.
Notice that for x=0 the Focusing distance is infinity but the DOF goes from 5.44m to -5.44m, let me clarify that I was trying to understand what happens when a lens is focused to the infinity mark. This looks like somewhat absurd to me but I thought it would be interesting to point that out.
The above table shows the depth of field range depending on the given focusing distance, here are the formulas used for the calculations:
Where Focus is the focusing distance in meters, DOF(i) is the initial depth of field distance (closest), DOF(f) is the final depth of field distance (farthest), and H is the hyperfocal distance.
Probably looking at all this numbers is confusing, here is a graph that illustrates the table above. The y axis represents meters. The x axis is the value used to divide the hyperfocal distance (H).
This is how depth of field works on a lens and the hyperfocal distance is something to be expected when we use the formulas above, remember that any number divided by zero is considered undefined. In other words you could cut a cake in pieces for eternity, in this case that means infinity.
The graph shows the amount of depth of field that you will get given the conditions described on the left side of it. The bigger x value the shallower depth of field you get, y will never be 0 but it will be very close.
How do I calculate it?
There’s a mathematical formula for that:
H = Hyperfocal distance in mm
f = Lens focal length in mm
N = F-number
c = Circle of confusion in mm
I know, you must be wondering what the is the Circle of confusion. Well it is a bit complicated but here’s a short explanation.
The circle of confusion is the maximum diameter of a circle of light projected onto the image sensor that can not be distinguished from a point. This is actually what defines the depth of field. In other words is the maximum diameter of the circle projected onto one pixel with out interfering with the pixels aside.
There are predefined values for the Circle of Confusion depending on the image format, the value will vary from table to table. Honestly I don’t think that little variation is a big deal in real life because even using the correct value for an specific lens of certain brand, you will not be able to set the lens focusing ring to that exact hyperfocal distance anyway.
For the examples below I will be using the values of the following table as a reference (taken from here).
Example: Say I have a Nikon 50mm F1.8 lens mounted on a Nikon D610. I am before a beautiful landscape and I want the greatest depth of field I can get shooting at F16 with a tripod.
Given the above conditions, calculate the hyperfocal distance (H).
H = ?
f = 50
N = 16
c = 0.029
(H is in millimeters, I just converted it to meters in order to set the value on my lens)
Excellent, now I can set my focusing ring to 5.4 meters and I know I will get a great shot!
But lets break it down to numbers, as I mentioned before, my depth of field will go from half my hyperfocal distance all the way to infinity, this means that for this example it will go from 2.7m all the way to infinity.
But what if there’s a rock at 1.5m and I want it also to be in focus? Well in that case I need to do one of two things:
- Move back enough to be at least 2.7m away from that rock in order to get it in focus
- Set my aperture to F32 to get a hyperfocal distance of 2.7m and a depth of field that goes from 1.37m all the way to infinity
But since my lens’s minimum aperture is F16, the first option is the one that will work for me, unless I am standing at the edge of a cliff.
Since it’s totally unpractical to do all this at the moment of taking the shot, I have created tables for Full Frame and APS-C sensors, so that you can simply take the values according to your lenses and give it a try. Each table has different values because the Circle of confusion changes depending on the size of the sensor. Click on them for full size image.
Of course, I calculated H for every combination in the table, and yes, I know it is not common to shoot at 300mm with F8 and be able to set the focusing ring to 388.23m, but I did it out of curiosity.
Now, as an engineer I had to go crazy and compute calculations for H given the following conditions:
- F number range: 0.7 to 90 in thirds of stop
- Focal length range: 1mm to 600mm
- Image format: Full Frame (35mm)
Probably this is way too crazy but there you have it. The biggest of all hyperfocal distance tables (that I know of at the time of this writing). Click on it for full size image, be aware that it is a 55.1MB JPG file so be patient.
How do I focus at the hyperfocal distance?
It will depend on the lens you are using, here’s how to do it with a lens that…
- Has depth of field scale and distance scale: This is the easiest way to do it, you only need to set your focusing ring to the corresponding hyperfocal distance, you will notice that the ∞ mark is included in the depth of field scale. Here are examples of this type of lenses.
- Doesn’t have depth of field scale and has distance scale: Same as before just set your focusing ring to the corresponding hyperfocal distance, as you do not have a depth of field scale you will not be able to see if the ∞ mark is inside it so what I would do is take a test shot, check it and then make adjustments if needed. Here are examples of this type of lenses.
- Doesn’t have depth of field scale and distance scale: These the hardest, since there aren’t any scales on the lens, the most accurate method would be to focus at an object that is at the same distance as the hyperfocal distance, the problem, however, is to get it done accurate. Most modern lenses will be like this, but to be honest the work around for this is to simply focus at the longest distance possible and do some trial and error. Here is an example of this type of lenses.
What is the difference between focusing at the ∞ mark and focusing at the hyperfocal distance?
The difference is that you will get the greatest depth of field from a lens when you focus at the hyperfocal distance. Here are some examples, assume the circle of confusion is 0.029mm.
The first image shows a 50mm lens focused at the infinity and stopped down to F16. In this case we will get a depth of field ranging from 5 meters all the way to infinity (and beyond!) according to the scale.
The second image shows a lens focused at around 5.44 meters (hyperfocal distance) and stopped down to F16. In this case we will get a depth of field ranging from around 2.72 meters all the way to infinity according to the scale.
Here is another example of the above just with a different lens.
In conclusion, hyperfocal distance is the best option to get the greatest depth of field from a lens, this is useful mainly for landscape photography. On the other hand since now a days lens don’t have depth of field scales it is more common to just set a sharp manual focus with the help of live-view and do some trial and error. The other option is to simply use auto-focus.
I don’t think most people use this technique now a days but it is cool to know about it, who knows, maybe someday it will come in handy.