Landscape photographers often use the terms focusing distance and hyperfocal distance in relation to depth of field and image sharpness. These two terms are important in the context of creating tack sharp images of landscapes. Landscape images and sweeping vistas require a large part of the frame to be in sharp focus.
In this article we shall be looking at one specific term – hyperfocal distance. But before we get any further let’s recap a couple of those terms I mentioned about in the first paragraph.
Focusing distance is the distance between the subject or point of focus in an image and the optical center of the lens. If you draw an imaginary plane through that point of focus, everything on that plane would be in focus.
Depth of field is the extent of the image beyond and in front of the point of focus, that is also acceptably in focus. The other term that I mentioned was Hyperfocal Distance. Hyperfocal Distance relates to that distance, focusing wherein gives the maximum depth of field for a given aperture, sensor size and focal length. When you focus at the hyperfocal distance everything falling within half the distance to the point of focus and all the way to infinity will be acceptably in focus.
Hyperfocal distance is a calculation that is in significant use in landscape photography. It depends on the aperture that you use, the focal length of the lens in use, the sensor size as well as the focusing distance.
Depth of Field Calculators and Charts
Depth of field is a complicated mathematical calculation. Thankfully, however, you don’t have to do that on the field when shooting. There are depth of field calculators available online. You just need to enter a few details like the sensor size, the lens and the aperture and online depth of field calculators will give you printable charts on where to focus at. Print them out and you are ready to go. All you need to do is focus at the distance that has been given for the specific combination of lens, aperture and sensor size and you will have the maximum depth of field.
Shooting at Small Apertures Vs. Shooting at Hyperfocal Distance
It is a common misconception – using a small aperture will help you to maximize your depth of field. To an extent it is true. If you have an f/2.8 lens, stopping down to f/4, or further to f/5.6 or all the way to f/11 will certainly give you a progressive increase in depth of field. However, the smaller the aperture tends to get, higher are the chances of lens diffraction coming into play.
Lens diffraction relates to light getting scattered after hitting the lens diaphragm when the lens aperture is very small. Lens diffraction will produce softness in your images and you lose the advantage of stopping down after a while. For most lenses the sharpest aperture tends to be around f/8 and f/11. But even with a small aperture like that not knowing the distance at which to focus at will result in less depth of field than your lens is capable of producing. Thus, hyperfocal distance is a much better technique to produce the maximum depth of field.
Go for primes with depth of field and focusing distance indicators
The second thing to remember is wide angle lenses will produce slightly larger depth of field. As such it is pertinent to know, that if you need a large depth of field you will require a wide angle lens, preferably primes. The reason why I insist on primes is they don’t zoom. Zooming changes the focal length of the lens and with it the depth of field. Additionally, these lenses don’t always have the focusing distance indicator on them. Focusing distance indicator is a big help. Some older primes also have a depth of field indicator. These are absent in most modern zooms lenses. The depth of field indicator will give you an indication as to how much of the frame is in focus for the aperture that you are using.