Best Aperture for Landscape Photography: f/8, f/11, or f/16?

"f/8 and be there" is the old line, and it is not bad advice. But f/8 isn't always right and f/22 isn't always wrong. What decides it is how close your nearest object is, and how many pixels your sensor has.

Start with the nearest thing in the frame

For a landscape the question is usually how close the foreground can be while the horizon stays sharp. If you focus at the hyperfocal distance, everything from half that distance out to infinity is acceptably sharp. Here are the figures for full frame, using the usual circle of confusion. Each cell reads "focus at this distance / sharp from this distance".

So a 24 mm lens at f/11, focused at about 1.8 m, keeps everything from roughly 0.9 m to infinity sharp. These distances suit prints of a normal size. For very large prints, or if you inspect at 100 percent, treat them as slightly optimistic, which the circle of confusion post explains. The hyperfocal distance post covers how to focus in practice.

Why not just use f/22?

Diffraction. As the aperture closes, light spreads out slightly at the edge of the opening, and a point of light lands on the sensor as a small disc instead of a point. At f/11 that disc is about 15 micrometres across. On a 24 MP full-frame sensor, where pixels are about 5.9 micrometres, that is roughly 2.5 pixels. On a 45 MP sensor (4.4 micrometres) it is about 3.4 pixels. At f/16 the figures are 3.6 and 4.9 pixels. It is not a cliff, sharpness just slips as you go, and the higher the resolution the sooner you notice. The diffraction guide has more.

There are honest reasons to stop down anyway. A small aperture draws sunstars around the sun, and it lets you use a slow shutter on water in daylight without a neutral density filter. If the shot needs either, f/16 or f/22 is a fair price.

The sharpest aperture on your lens isn't always where the books say

Most lenses are sharpest somewhere around f/4 to f/8, and the corners often peak a stop or two later than the centre. The only way to know is to test. Put the camera on a tripod, shoot something flat and detailed at every stop, and compare at 100 percent. It takes about ten minutes and tells you more than a review.

What I would pick in the field

With no foreground, a distant mountain or a seascape, f/8 is plenty, and a stop wider is fine if the light is dim. With a foreground a metre or so away and a wide lens, f/11 focused near the hyperfocal distance covers it. Closer than about 50 cm, no single frame will do the job. At 24 mm and f/22 the nearest sharp distance, with infinity still sharp, is about 47 cm. At f/16 it is 64 cm. So rocks 20 cm from the lens plus a horizon is out of reach in one frame at any aperture. Shoot two or three frames at f/8 to f/11 and combine them, as described in the focus stacking post.

Smaller sensors

On APS-C, every f-number gives the depth of field of a number about 1.5 times larger on full frame, so f/8 behaves like f/12 at the same framing. For Micro Four Thirds it is double, so f/5.6 behaves like f/11. Diffraction arrives sooner too, because the pixels are smaller. A 20 MP Micro Four Thirds sensor has 3.3 micrometre pixels, and the diffraction disc is already about 3.3 pixels across at f/8. That is why you can stop down less on small sensors and still get the depth you need.

When you do not want everything sharp

A lone tree against a soft hillside, or a flower in front of a misty valley, often looks better at f/2.8 to f/5.6. Low light is another reason: a wider aperture at a low ISO can beat f/11 at a high one. Landscape depth of field is a choice. It is only a rule if you decide it is.

To test a particular lens and distance, enter them in the calculator and read off the near and far limits.

Related reading: What is Depth of Field?, 7 DOF Myths Debunked.