Depth of field is the stretch of the scene that looks acceptably sharp. Four things control it: aperture, focal length, subject distance and sensor size. This sheet shows how each one pushes the zone wider or narrower, and adds a walkthrough, common scenarios and a troubleshooting table.
What Changes It
| Factor | For shallow depth | For deep depth |
|---|---|---|
| Aperture | Wide opening (low f-number) | Small opening (high f-number) |
| Focal length | Longer lens | Wider lens |
| Distance to subject | Closer | Farther |
| Sensor size | Larger sensor | Smaller sensor |
Typical Apertures by Subject
- Single portrait with a soft background: around f/1.8 to f/2.8
- Couple or small group: around f/4 to f/5.6, so everyone stays sharp
- Street and general scenes: f/5.6 to f/8
- Landscapes with foreground interest: f/8 to f/11
- Close-up of small objects: f/8 to f/16, since the zone is very thin up close
Quick Technique
- Decide what must be sharp and what can blur.
- Choose the aperture from the list above.
- Adjust shutter speed or ISO to keep exposure correct.
- Focus on the key point, such as the nearest eye.
- Check the result zoomed in on the screen and adjust.
Landscape Focus Tip
For scenes with near and far detail, focus roughly one third of the way into the scene, and use a middle aperture. Some lenses show distance scales, and the maker’s guide may describe hyperfocal focusing.
Watch Out For
- Very small apertures can soften detail through diffraction.
- Wide apertures magnify focus errors, so aim carefully.
- Blur quality varies between lenses, even at the same f-number.
Background distance matters as much as the aperture. A subject standing close to a wall will not show much blur, even at a wide opening, whereas moving the subject well away from the background increases separation. Moving yourself closer to the subject adds to the effect, so a small step often does more than a change of setting.
Many cameras offer a depth-of-field button or live view that shows the chosen aperture on the screen. Use it to judge the result before pressing the shutter.
For portraits, focus on the eye closest to the camera, and keep the face roughly parallel to the sensor so both eyes lie in the sharp zone. For groups, line people up at a similar distance. For close-ups, consider shooting several frames at slightly different focus points and combining them in editing, a method often called focus stacking.
When in doubt, take one frame at a wide aperture and one at a medium one, then compare them on a larger screen at home.
A Worked Walkthrough
Suppose you want a portrait of a friend outdoors with a softly blurred background.
- Choose a spot where the background is far behind your friend, such as trees or buildings a good distance away, rather than a nearby wall.
- Set the camera to aperture priority or manual mode, and choose a wide aperture within the range for single portraits.
- Use a longer focal length if your lens allows it, and step a little closer to your subject, both of which narrow the sharp zone.
- Place the focus point on the nearest eye and take a frame.
- Zoom in on the screen. If the eyelashes are sharp and the ears are slightly soft, the zone is working for you. If the whole face is soft, check focus and consider a slightly smaller aperture.
- If the background is still distracting, increase the distance between your friend and the background, or change your angle.
Common Scenarios
Group photo on a patio
People stand at slightly different distances, so a small aperture keeps everyone sharp. Line them up in a shallow row, and focus on someone in the middle rather than the nearest face.
Flower or insect close-up
The sharp zone can be only a few millimetres deep. Use a smaller aperture, position the camera parallel to the subject, and focus on the feature that matters most.
Landscape with a foreground rock
Choose a middle aperture and focus about a third of the way into the scene so both rock and horizon look acceptably sharp. Check detail at full size after shooting.
Street scenes
A middle aperture and a moderate distance keep moving subjects within a forgiving zone. This helps when you cannot refocus quickly.
Product on a table
Items are close, so the zone is thin. A smaller aperture and a steady support help, and background distance gives the separation you want.
Mistakes to Avoid
| Mistake | Why it matters |
|---|---|
| Using the widest aperture for groups | Faces at different distances fall out of the sharp zone |
| Going to the smallest aperture for everything | Diffraction softens detail and the shutter speed becomes slow |
| Focusing and recomposing at close range | The small shift moves the focus plane off the target |
| Ignoring background distance | A nearby background stays sharp even at a wide aperture |
| Trusting a small screen | Slight focus misses only show when you zoom in or view on a larger display |
Quick Troubleshooting
| Symptom | Likely cause | What to try |
|---|---|---|
| Eyes soft, ears sharp | Focus landed behind the target | Refocus on the nearest eye and retake |
| Not enough blur | Background too close or aperture too small | Move the subject away from the background, or widen the aperture |
| Foreground and background both soft | Aperture too wide for the scene | Close the aperture and focus a third into the scene |
| Everything slightly soft | Very small aperture or camera shake | Open up a stop or two, or use a steadier support |
Terms Worth Knowing
- Aperture
- The opening in the lens that controls how much light passes and affects depth of field.
- F-number
- The figure that describes the aperture, where a lower number means a wider opening.
- Focus plane
- The distance at which the subject is sharpest.
- Hyperfocal distance
- A focus distance that makes the zone reach from a near point out to infinity.
- Bokeh
- The look of out-of-focus areas in a photograph.
- Focus stacking
- Combining frames focused at different distances to extend the sharp zone.
FAQ
Is more blur always better?
No. Blur helps isolate a subject, but sharp surroundings can tell a story. Choose based on the message.
Why are my close-ups partly blurred?
At short distances the sharp zone is just a sliver. Use a smaller aperture or step back.
Does a phone have shallow depth of field?
Phone sensors are small, so natural blur is limited. Many phones simulate background blur with software, which can look different from blur created by a large sensor and wide aperture.
What does f/2.8 mean compared with f/8?
The lower number is a wider opening. At f/2.8 more light enters and the sharp zone is thinner, while at f/8 less light enters and the sharp zone is deeper.
Does focal length change depth of field by itself?
For the same subject distance, a longer lens gives a thinner zone. If you move back to keep the subject the same size, much of that difference reduces, so the effect depends on how you frame.
Which setting should I change first?
Change the aperture first, because it is quick and its effect is clear. Then adjust your distance to the subject and the background to refine the look.
The Short Version
Wide aperture, long lens and close distance give a shallow zone; small aperture, wide lens and distance give a deep one. Set the aperture for the look you want, then balance exposure. Check focus at full size before you move on.