If you want sharper portraits, cleaner backgrounds, or better low-light photos, learning how to change aperture on DSLR cameras is one of the most useful skills you can build.
The trick is knowing which camera mode gives you control, where the aperture setting lives, and how that number changes your image.
What aperture does on a DSLR
Aperture is the opening inside the lens that lets light reach the camera sensor.
It is measured in f-stops, such as f/1.8, f/4, or f/11, and those numbers control both brightness and depth of field.
A wider aperture uses a smaller f-number and lets in more light.
A narrower aperture uses a larger f-number and lets in less light.
- Wide aperture such as f/1.8 or f/2.8: brighter image, blurrier background, shallower depth of field
- Mid aperture such as f/4 or f/5.6: balanced light and focus
- Narrow aperture such as f/8, f/11, or f/16: darker image, more of the scene in focus
This is why aperture matters so much in portrait photography, landscape photography, sports, and low-light work.
It is not just a technical setting; it is one of the main ways you shape the look of a photo.
How to change aperture on DSLR cameras
The exact controls depend on the camera brand, but the process is similar across Canon, Nikon, Sony, Pentax, and other DSLR systems.
- Turn the mode dial to Aperture Priority, usually marked A or Av.
- Use the main command dial or rear dial to change the f-stop.
- Watch the aperture value in the viewfinder or on the rear screen.
- Half-press the shutter button to confirm exposure changes if needed.
In Aperture Priority mode, you choose the aperture and the camera selects the shutter speed automatically.
This is the easiest mode for learning how aperture affects exposure without having to manage every setting at once.
If you use Manual mode, aperture is still changed with the same dial, but you must set shutter speed and ISO yourself.
This gives full control but requires more attention to exposure balance.
Where is the aperture setting located?
Most DSLRs use one of two common layouts.
Some cameras have a front command dial near the shutter button, while others use a rear dial or multi-function wheel.
Higher-end models may have two dials, letting you change aperture and shutter speed separately in Manual mode.
If your camera lens has an aperture ring, you may be able to adjust aperture directly on the lens.
This is more common on older manual-focus lenses and certain specialty lenses.
On most modern DSLR lenses, aperture is controlled electronically from the camera body.
How do you know if the lens supports aperture control?
Look for an aperture scale on the lens barrel or check the lens mount information in the manual.
Many modern DSLR lenses do not have a physical aperture ring, so the body controls the diaphragm through electronic contacts.
If the lens is fully manual, you may need to switch the camera to manual exposure and ensure the lens is set to the desired aperture before shooting.
What the f-number actually means
The f-number is a ratio, not a simple measurement of opening size.
A lower number means a wider opening because the lens opening is larger relative to the focal length.
A higher number means a smaller opening.
That is why f/2.8 lets in more light than f/8.
It also means that when you change aperture, the camera often compensates by adjusting shutter speed or ISO to maintain a proper exposure.
- f/1.4 to f/2.8 for low light and strong background blur
- f/4 to f/5.6 for general photography and moderate subject separation
- f/8 to f/11 for landscapes, architecture, and greater depth of field
How aperture affects exposure, depth of field, and sharpness
Changing aperture affects three important parts of the image: brightness, depth of field, and lens performance.
These work together, so the best aperture depends on what you want the photo to look like.
Exposure
A wider aperture brightens the image.
A narrower aperture darkens it.
If you open the aperture by one stop, you double the amount of light.
If you close it by one stop, you cut the light in half.
Depth of field
Depth of field is the zone that appears sharp in front of and behind the focus point.
A wide aperture gives a shallow depth of field, which is useful for portraits and close-up detail.
A narrow aperture gives a deeper depth of field, which helps keep more of a landscape or group photo in focus.
Sharpness and lens sweet spot
Most DSLR lenses are sharpest in the middle of their aperture range, often around f/5.6 to f/8.
Extremely wide apertures can soften edges, and very narrow apertures can introduce diffraction, which slightly reduces detail.
That means the most open or most closed setting is not always the best choice for maximum image quality.
Best aperture settings for common photography types
The right aperture depends on subject, lens, lighting, and creative intent.
These starting points work well for many DSLR users.
- Portraits: f/1.8 to f/4 for soft backgrounds and subject separation
- Landscapes: f/8 to f/11 for edge-to-edge detail
- Group photos: f/5.6 to f/8 so multiple rows stay sharp
- Macro photography: f/8 to f/16 for more depth of field
- Sports and action: f/2.8 to f/5.6 to allow faster shutter speeds
If the light is dim, you may need to open the aperture wider or raise ISO to avoid motion blur from a slow shutter speed.
How to change aperture on DSLR in Manual mode
Manual mode gives you full control over aperture, shutter speed, and ISO.
To change aperture, rotate the camera’s assigned control dial until the desired f-number appears on the display.
In many Canon DSLRs, this is done with the main dial while holding the shutter button or a dedicated exposure button, depending on the model.
On many Nikon DSLRs, the command dial changes aperture in Manual mode after you enable the correct control behavior in the menu.
The camera manual matters here because button and dial assignments vary by model.
When shooting in Manual mode, check the exposure meter in the viewfinder or on the screen.
If the meter shows underexposure after you close the aperture, you may need a slower shutter speed or higher ISO.
Common problems when changing aperture
Sometimes aperture does not seem to change the way you expect.
A few common issues can explain why.
- Wrong mode: In Auto or Scene modes, the camera may block aperture changes.
- Kit lens limits: Some zoom lenses have a variable maximum aperture, such as f/3.5-5.6.
- Lens not fully mounted: Poor contact between lens and body can prevent electronic control.
- Exposure mode restrictions: Certain modes override or limit manual settings.
- Using flash: Flash exposure can make aperture changes seem less obvious in bright scenes.
If the dial changes nothing, remove and remount the lens, verify the camera is in A/Av or Manual mode, and check whether the lens is set to autofocus and properly connected.
How to practice aperture control quickly
The fastest way to learn aperture is to test the same subject at different settings.
Photograph a single object, a portrait subject, or a simple scene while moving from wide to narrow apertures one stop at a time.
- Set the camera to Aperture Priority.
- Take one photo at f/2.8.
- Increase to f/4, then f/5.6, then f/8.
- Compare background blur, brightness, and detail in the images.
This simple exercise makes the relationship between aperture, light, and focus much easier to understand than reading about it alone.
Once you can predict the effect of each f-stop, you will use aperture more confidently in real shooting situations.
Quick reference for aperture control on DSLRs
- Use Aperture Priority for the easiest control
- Use Manual mode for full creative control
- Lower f-number = wider aperture = more light
- Higher f-number = narrower aperture = less light
- Wide apertures blur backgrounds
- Narrow apertures keep more of the scene in focus
Learning how to change aperture on DSLR cameras gives you direct control over the visual style of your photos, from dramatic background blur to detailed, fully sharp scenes.