This week I thought it was time to think about one of the technical aspects of photography. We are going to look at “Hyperfocal Distance”. I would classify this as intermediate level training and it is something that I cover on my intermediate level events. So….
What is hyperfocal distance?
When you focus on a particular point you have an area of acceptable focus in front of where you are focusing and an area behind. This is your depth of field.
Approximately two thirds of the depth of field lies behind the focus point. Thus if you focus on “infinity” this extra distance that is in focus will be lost.
Hyperfocal distance is the position where you need to focus so that everything from the focus point to infinity is in acceptable focus. Landscape photographers use this to get the maximum depth of field for their images.
For the real techies here is a very accurate and technical definition of hyperfocal distance:
- “The hyperfocal distance is the closest distance at which a lens can be focused while keeping objects at infinity acceptably sharp; that is, the focus distance with the maximum depth of field. When the lens is focused at this distance, all objects at distances from half of the hyperfocal distance out to infinity will be acceptably sharp.”
Or to put it more simply (ie a definition for the rest of us):
- “Hyperfocal distance is where you focus to keep objects at infinity in focus and get the maximum depth of field.”
Some lenses have a hyperfocal distance scale on them (less common these days). To use the scale you set the “infinity” distance on the focusing ring to the marker indicating the current f-stop. When set to this we get the maximum depth of field, and all objects at infinity will be acceptably in focus.
(Above image is public domain via Wikipedia image created by “Mark Sweep”)
The above image shows a lens with a hyperfocal distance scale on it. The markings are for f/22, f/16 and f/11. Assuming the lens was set to an aperture of f/22, we would set the infinity marker to the “22” mark on the left of the focus indicator. The nearest point in focus could then be read by looking at the “22” marking to the right of the focus point indicator, ie 0.7m
The same scale can also be used to calculate depth of field for any setting. As shown this lens is set to f/11. We can then see from the scale that everything between 1m and 2m will be in acceptable focus.
Modern lenses no longer include a DOF scale, or hyperfocal distance markings inscribed on them. However iPhone, android apps are available to calculate the hyperfocal distance. For iPhone/iPad I recommend the “Martin Bailey Podcast Companion App” which has a depth of field calculator, that shows hyperfocal distance. (It also allows you to easily listen to Martin’s excellent podcasts).
For those without either, applications are available that can be used on PC or Mac and which allow you to create a paper-based calculator. See: http://www.dofmaster.com/ for details of all of these.
Until next time, keep MAKING great photographs,