How to Calculate and Shoot Images with the Correct Depth of Field
Understanding “Hyperfocal Distance” – This sounds like one of those technical terms that is reserved for the realms of the professional photographer but it is actually something that once understood, can change the quality of shots for any photographer.
In a nutshell, hyperfocal distance (HFD) is the point of focus where everything in the frame from half the hyperfocal distance to infinity falls within the depth of field or focus range…or simply the setting that produces the greatest depth of field.
For example, let’s say the HFD for your current camera and settings is 20 meters, if you were to focus on that point, everything from 10 meters to infinity would be sharp, or in focus.
Now the hyperfocal distance of any shot all depends on four factors:
- Sensor Size
- Aperture Setting
- Focal Length of Lens
- Subject Distance
So what is the importance of this?
Well, many beginner landscape photographers make one of two mistakes. They either focus on infinity, i.e. the furthest distance (normally the horizon), or an object in the foreground.
In either instance, if the calculations are out, you will have either a sharp horizon and blurry foreground (first shot above), or you will have the object in the foreground sharp and the rest of the image blurred.
A common mistake to make and one that can frustrate many photographers.
Let’s take an example to illustrate this further.
Hyperfocal Distance Example
Say you are photographing a subject that is 20 feet away and you want them plus everything else in focus AND you are using the following camera and settings:
- Sensor Size: Full Frame (Canon EOS 5D Mark III)
- Aperture: F8
- Focal Length of Lens: 50mm
- Subject Distance: 20 Feet
If you were to focus on the actual subject 20 feet away, your near limit of focus would be 12.7 feet and your far limit of focus would be 47.7 feet. That means anything closer than 12.7 feet and further away than 47.7 feet would be blurred.
Total depth of field (stuff in focus) = 35 feet
Now, once we establish the HFD, which in this case using those settings and particular camera (sensor size) is 34.3 feet, we can focus on THAT point to give us a much different outcome.
By focussing at 34.3 feet instead of 20 feet, and even though we are focussing PAST or behind the subject, our near limit of focus becomes 17.15 feet (slightly further away than the 12.7 feet previously but just before the subject which is good as the subject is still in focus) and our far limit extends to infinity meaning everything behind the subject should be in focus too.
So all we are doing is changing the point at which we focus and NOT any of the settings, we can alter what in the final photograph is in focus…genius!
I hope you can see the benefits of this?
I feel after taking hundreds of thousands of photos over the years, that even without using all these charts and rules, I kind of instinctively know where to focus for best effect but that just comes from tons and tons of practise and analyzing my photos over the years.
It is worth playing with this and learning as much as you can because it will no doubt help with all manner of photography:
- Weddings – Learn where to focus for best depth of field for group shots, portraits and so on
- Stock Photography – Focus and depth of field can make or break a shot with stock photography whether it is a landscape, cityscape, portrait or product shot
- Landscape Photography – Probably the most shot subject where hyperfocal distance plays a large part
Which Lenses are Best for Hyperfocal Distance?
Any lens from standard (50mm) to wide angle (10mm-35mm) would work well here because these lenses have quite short hyperfocal distance when set with large apertures such as f16. This is why such lenses are best used for landscape photography.
For example, a 16mm lens set to f16 on a full frame sensor (Canon 5D Mark III or Nikon D800) has a HFD of just 1.8 feet. This means that if you focussed at that point, everything from 0.9 feet to infinity would be in focus.
At the other end of the spectrum, a telephoto lens of 200mm set to f16 on a full framed camera would have a hyperfocal distance of 274.1 feet meaning that you by focussing at that point, you would get everything from 137.05 feet to infinity in focus. Useless if your subject is closer than 137 feet away and by focussing on the subject at say 50 or 100 feet, you would have a blurry background.
Check out these two photos taken on top of Portland in Dorset overlooking Chesil Beach. Both were taken using a 200mm lens on a full frame camera with an aperture of f8.
These settings give a hyperfocal distance of 547 feet.
Clearly, by focussing much closer than the hyperfocal distance in this first shot (they were about 50 feet away), the subject is in focus but the background is completely blurred.
However, by taking the foreground out of the equation and focussing way past the hyperfocal distance, the same settings on the same camera give me incredible depth of field with everything in focus from the foreground right to through to infinity.
This is why some people are confused when they use a small aperture of say f16 on a telephoto lens but still get shallow depth of field…it is all about hyperfocal distance.
Using an aperture of f16 on a telephoto lens, your subject would need to be no closer than a whopping 137 feet if you wanted them and everything behind to infinity in focus. Bear this in mind when next using a telephoto lens.
This is why portrait shooters use mid to long telephoto lenses such as 85mm or 160mm. They give shallow depth of field creating a beautiful bokeh or blur in the background.
Here is another example using a 50mm lens at f9 which most people would think would give excellent depth of field in any situation. The HFD using a 50mm lens at f9 on a full frame camera is 30.6 feet meaning everything from 15.3 feet to infinity will be in focus when focussing at that point (HF distance of 30.6 feet).
In this photo, I focussed on my son in the distance which is well past the HFD and everything from 15 feet to infinity is in focus.
100% Crop (quality reduced for web)
Whereas in this next shot, I focussed before (or in front of) the hyperfocal distance of 30.6 feet and as you can see, the foreground subject is in focus but the background is blurred.
Make sense? If not, read it all again or…
Try it Yourself – Handy Tools
The best way to learn and practise using Hyperfocal Distance is to use the Depth of Field Calculator and also print off and carry a reference chart like the one below (this is for 35mm or full frame cameras but you can Google search for others) that shows focal points and distances.
Go to DOF Calculator using the link above and put in various settings and watch the changes between “Focus at Subject Distance” and Focus at the Hyperfocal Distance”.
Once you have a basic understanding, get out with your camera and take some test shots and start to get the feel of shooting and focussing at the Hyperfocal Distance and opposed to the Subject Distance…great stuff!