Canon R100 Background Blur: Aperture, Distance and Lenses

To blur the background on the Canon EOS R100, open your lens to its smallest f-number, step close to your subject, and move them far away from whatever is behind them. Then zoom toward the long end of your lens, and if the kit lens still is not giving you enough softness, a bright prime lens makes the job much easier.

Why the R100 can blur a background

The EOS R100 uses an APS-C size sensor with 24.1 million pixels. Canon lists natural background blur as one of the things an APS-C mirrorless camera like this can do that sets it apart from a smartphone. Digital Camera World's review notes the sensor lets you achieve shallow depth of field.

Depth of field is the slice of your picture that looks sharp. Think of a flashlight beam in fog: a thin beam lights up one thin slice, and everything in front and behind fades away. A shallow depth of field means a thin slice, so your subject is sharp and the background melts into soft color.

The soft, blurry part has a name too: bokeh. When people say a photo has nice bokeh, they mean the blurry background looks smooth and pleasant.

You do not need an expensive camera to get this look. You need four simple levers, and the R100 gives you all of them.

R100 feature	What it means for blur
24.1MP APS-C sensor	Big enough for natural background blur
1.6x crop factor	Lenses look more zoomed in than their number
Dual Pixel CMOS AF, up to 143 areas	Helps land focus on a thin slice
Eye Detection	Puts focus on the eyes for portraits
Fixed, non-touch 3-inch screen	Settings are changed with buttons

The four levers that control background blur

1. Aperture: the pupil of your lens

The aperture is a hole inside the lens that opens and closes, just like the pupil of your eye. In a dark room your pupil gets big. In bright sun it gets small.

The size of that hole is written as an f-number, like f/4.5 or f/8. Here is the part that confuses almost everyone at first, so do not worry if it feels backward: a small number means a big opening. f/1.4 is a wide-open pupil. f/11 is a squint.

A wide opening gives you a thin slice of focus and more background blur. So for blur, you want the smallest f-number your lens will allow.

2. Distance from you to your subject

The closer you stand to your subject, the blurrier the background gets. Try this: hold one finger near your face and look at it. The room behind it goes soft. Now hold your finger at arm's length. The room gets clearer. Your camera works the same way.

Get as close as your lens lets you focus while still framing the picture you want. A head and shoulders portrait will have much more blur than a full body shot from across the yard.

3. Distance from your subject to the background

This lever is free, and it is often the biggest win. If your friend stands with their back against a brick wall, that wall stays fairly sharp no matter what you do. Ask them to take ten big steps away from the wall, toward you, and the bricks turn into soft texture.

Look for backgrounds that are far away: an open field, a street that runs off into the distance, or trees on the other side of a park.

4. Focal length: how far you zoom

Focal length is how zoomed in your lens is, measured in millimeters. 18mm is wide and shows a lot of the scene. 45mm is more zoomed in.

A longer focal length makes the background look bigger and softer behind your subject. So when you want blur, zoom in and step back to keep the same framing.

The R100 has a 1.6x crop factor. That means a 45mm lens frames a scene roughly the way a 72mm lens would on a full-frame camera. Your lenses act a little more zoomed in than the number on the barrel suggests.

Step by step: R100 settings for a blurry background

Digital Camera World says the R100 shows its real strengths when you move into semiautomatic and manual modes. Aperture priority is the gentlest place to start.

1. Turn the mode dial to Av. Av mode means you choose the aperture and the camera chooses the shutter speed. It is like riding a tandem bike: you steer, and your partner handles the pedaling.
2. Turn the dial to the smallest f-number. With the kit lens, that is the lowest number it will show at your current zoom.
3. Set ISO to Auto while you learn. The camera keeps the picture bright so you can think only about blur.
4. Use face and eye focus. The R100 has Eye Detection that Canon says can find human eyes with high accuracy, even from long distances.
5. Zoom in, step close, and move your subject away from the background.
6. Take the shot, then magnify it on the screen to check the eyes are sharp.

The R100 has only one control dial, and PetaPixel's review found switching between exposure settings clunky. The rear screen is not touch sensitive, so you move through settings with buttons. That is a little slower, but Av mode helps because you are only changing one thing: the aperture.

Focus matters more when the blur gets strong

When the slice of sharpness is thin, a small focus miss shows. If the camera focuses on the ear instead of the eyes, the face can look soft even though the background looks lovely. That is not a failure. It is proof the slice is thin, which is exactly the look you asked for.

The R100 uses Dual Pixel CMOS AF with up to 143 focus areas. For people who are sitting still, One-Shot AF works well. For a moving child or pet, Canon says Eye Detection also works on moving subjects in Servo AF. Servo AF keeps refocusing as your subject moves, like a dog's eyes following a thrown ball.

The R100 shoots up to about 6.5 frames per second in One-Shot AF and about 3.5 in Servo AF. For portraits, either is plenty.

Getting blur from the kit lens

If you bought the kit, your lens is the Canon RF-S 18-45mm F4.5-6.3 IS STM.

The F4.5-6.3 in the name is the range of its widest aperture as you zoom from 18mm to 45mm. Those are not very wide openings. PetaPixel calls the aperture range weak, and TechRadar describes the kit lens as pretty basic.

You can still get real background blur from this lens. You just lean harder on the other three levers.

• Zoom all the way to 45mm. The f-number climbs a little, but the longer zoom usually adds more blur than you lose.
• Fill the frame with your subject, head and shoulders, and get as close as the lens will focus.
• Pull your subject far from the background. Ten steps or more is a good habit.
• Choose a calm background, like leafy trees in shade, rather than busy lines and signs.

Small flowers, a coffee cup, a pet's face: close subjects with a faraway background are where the kit lens gives you its softest backgrounds.

Lenses that make background blur easy

If you want blur without working so hard, a lens with a smaller f-number is the biggest upgrade. The R100 works with the full lineup of RF and RF-S lenses, and EF and EF-S lenses work through Canon's EF-EOS R mount adapters.

A prime lens does not zoom. Many primes open much wider than a kit zoom, which is why photographers reach for them when they want soft backgrounds.

Lens	Widest aperture	Focal length	Full-frame look (x1.6)	Why it helps
Canon RF-S 18-45mm F4.5-6.3 IS STM	f/4.5 to f/6.3	18-45mm	About 29-72mm	Comes in the kit
Canon RF 28mm f/2.8 STM	f/2.8	28mm	About 45mm	Tiny pancake, wider than the kit lens
Sigma 56mm f/1.4 DC DN Contemporary	f/1.4	56mm	About 90mm	TechRadar's pick for a second lens
Canon RF-S 55-210mm F5-7.1 IS STM	f/5 to f/7.1	55-210mm	About 88-336mm	Long reach, in the two-lens kit

Canon RF 28mm f/2.8 STM

This pancake lens was released at the same time as the R100. Digital Camera World's reviewer found the camera most portable when paired with lightweight primes like it. At f/2.8 it opens wider than the kit lens's f/4.5, so you get a bit more blur from a lens small enough to leave on all day.

Sigma 56mm f/1.4 DC DN Contemporary

When PetaPixel reviewed the R100 in 2023, it noted there were almost no third-party lens options for the camera. TechRadar's later review reports that Canon opened the RF mount to third-party APS-C lenses and Sigma released RF versions of its DC DN Contemporary lenses. TechRadar's reviewer highly recommends the Sigma 56mm f/1.4 DC DN Contemporary as a second lens after the 18-45mm kit lens.

At f/1.4 the opening is far wider than the kit lens, and with the 1.6x crop factor a 56mm lens frames about like a 90mm lens on full frame. A wide pupil plus a longer view is a classic portrait recipe.

Canon RF-S 55-210mm F5-7.1 IS STM

This telephoto zoom comes in the R100's two-lens kit. Its long reach can turn a faraway background soft even though its aperture is not wide. TechRadar found it decent, but noted an onion-ring effect in the bokeh of a cat portrait. Onion-ring bokeh means the soft blobs of light in the background show faint rings inside them, like a sliced onion.

Adapted EF lenses

The Digital Picture's review says EF and EF-S lenses work through a Canon Mount Adapter EF-EOS R and perform as native. If someone in your family has older Canon DSLR lenses, try them on the R100 before you buy anything new.

Background blur in video

The four levers work the same way in video, but the R100 has a few limits to plan around. In 4K, the camera crops the image by 1.55x and uses slower contrast autofocus instead of Dual Pixel CMOS AF. PetaPixel found subjects tended to drift in and out of focus in 4K 24p.

You only get Dual Pixel CMOS AF if you drop down to Full HD, and the R100 records full-width Full HD at up to 60 frames per second. With a thin slice of focus, steady focus matters a lot, so Full HD is the safer choice for blurry-background talking shots on this camera.

Common blur mistakes, and what they teach you

• The background is still sharp. Usually the subject is standing too close to whatever is behind them. Move them forward, zoom in, and step closer. You just learned which lever matters most.
• The background is blurry but the face is soft. Focus landed somewhere other than the eyes. Use eye detection and magnify a test shot on the screen.
• Only part of a group is sharp. With people standing at different distances, a very small f-number can leave the back row soft. Line everyone up side by side, or raise the f-number a little. Save this lesson for later: blur is a dial, not a switch.
• The whole photo is blurry. That is usually motion blur from a slow shutter speed, not background blur. In dim light, Av mode may choose a slow shutter, so add light, hold the camera steadier, or let ISO rise.

Where to go next

Practice one lever at a time. Take the same portrait at 18mm and at 45mm. Take it with your subject against a wall, then ten steps away. Seeing the change with your own eyes teaches you faster than any chart.

Digital Camera World calls the R100 the mirrorless replacement for the Rebel SL2 and T7 DSLRs. If you also have a T7, the Canon Rebel T7 background blur guide walks through Av mode on that camera. The R100 is very similar in size and layout to the Canon EOS R50, and the Canon R50 background blur guide covers that body. Still choosing a camera? See Best Canon Camera for Beginners in 2026.

If you want these settings on one card in your camera bag, the settings cheat sheets in thecamera.school store put Av mode, aperture and focus steps in one place.