You’ve probably seen it. A propeller on a plane looks like a bunch of detached, floating bananas. A golf club bends like it’s made of rubber right at the moment of impact. Maybe you were filming out a car window and the telephone poles look like they’re leaning at a 45-degree angle.
It’s weird. It looks like a glitch in the matrix. But it isn't a ghost in the machine or a broken lens. It's just rolling shutter.
Most people think a camera takes a picture of a single moment in time. Like, snap, and the whole frame is captured. That’s how old film cameras with "global shutters" worked. But the smartphone in your pocket and that shiny mirrorless camera you bought don't usually work that way. They read the image line by line. Top to bottom. Left to right. It happens fast, but not fast enough to keep up with a spinning blade or a speeding car.
The technical reality of the rolling shutter effect
Let's get into the weeds for a second. Most modern CMOS sensors—the chips that actually "see" the light—don't have the circuitry to record every single pixel at the exact same nanosecond. It’s a space-saving thing. By reading the sensor row by row, manufacturers can keep cameras small, cheap, and power-efficient.
Think of it like a flatbed scanner. You know how the light bar moves across the paper? If you wiggle the paper while it's scanning, the image comes out looking like a melted candle. A CMOS sensor does the exact same thing, just way faster. Usually, it takes about 1/30th to 1/60th of a second to read the whole sensor. That sounds instantaneous to a human, but to a physics-defying golf swing? It’s an eternity.
When the top of the frame is recorded, the golf club is at the top of the swing. By the time the sensor gets to the bottom of the frame, the club has moved six inches. The camera records both positions in the same "still" image. The result is a curved club that looks like a pool noodle.
Why does this keep happening?
Honestly, it's a trade-off. We want 48-megapixel photos and 4K video in a device that fits in a skinny jean pocket. To get that, we sacrifice the "Global Shutter." A global shutter turns every pixel on and off at the exact same time. It’s beautiful. It’s crisp. It’s also incredibly expensive and difficult to manufacture without adding a ton of electronic "noise" to the image.
Sony recently shook things up with the Alpha 9 III, which features a full-frame global shutter sensor. It’s a big deal in the industry because it finally kills rolling shutter artifacts for professional sports photographers. But for the rest of us using iPhones, Pixels, or even mid-range Canons, we're stuck with the "rolling" method for the foreseeable future.
How to spot it in the wild
You’ll see it most often in three specific scenarios:
The Jello Effect. This happens when the camera itself is vibrating. Think of a GoPro mounted to a motorcycle handlebar or a drone with unbalanced propellers. The high-frequency vibration causes the "lines" of the image to shift back and forth rapidly. The footage looks like it’s made of gelatin. It’s nauseating to watch and notoriously hard to fix in post-production.
Skew. This is the "leaning building" look. If you’re panning the camera quickly from left to right, the vertical lines in the background will tilt. This is because the top of the sensor captured the building when you were pointed at point A, but the bottom of the sensor didn't finish until you were pointed at point B.
Partial Exposure. This one is a nightmare for wedding photographers. If a flash goes off halfway through the sensor readout, you’ll get a photo where the top half is bright and the bottom half is dark. The sensor simply wasn't "open" long enough for the flash to hit the whole thing.
Can you actually fix it?
Yes and no. Mostly no.
If you’re a video editor, you might use a tool like the "Rolling Shutter Repair" effect in Adobe Premiere Pro or DaVinci Resolve. These plugins try to use motion estimation to "straighten out" the pixels. They work okay for minor skew. They are almost useless for heavy jello or fast-spinning objects.
The better way is to prevent it.
- Increase your shutter speed? Nope. That’s a common misconception. A faster shutter speed makes the individual lines sharper, but it doesn't change how fast the sensor reads those lines. In fact, a very high shutter speed can sometimes make rolling shutter look worse because there’s no motion blur to hide the distortion.
- Use a gimbal. If you stop the camera from shaking, you stop the jello. It's the most effective way to handle smartphone video.
- Avoid fast pans. Move the camera like it’s a heavy, expensive piece of machinery. Slow, deliberate movements keep the skew to a minimum.
The physics of the "Propeller Paradox"
There is something deeply cool about how rolling shutter interacts with circular motion. When a propeller spins, it creates those weird, detached blades. This happens because the speed of the blade matches or interacts with the "scan rate" of the sensor.
In some frames, the blade might be moving in the same direction as the scan, making it look stretched. In others, it’s moving against the scan, making it look compressed or tucked into itself. Scientists and hobbyists have actually used this effect to "visualize" the speed of objects, but for most people, it's just a ruined shot of a cool plane.
Does it matter for photography?
Usually, it doesn’t. If you’re taking a picture of a landscape or a person standing still, you will never notice it. The sensor reads fast enough that a person’s blink or a leaf fluttering won't cause visible distortion.
It only matters when the subject is moving at extreme speeds or when the camera is being shaken violently. This is why professional sports photographers have been so obsessed with mechanical shutters for decades. A mechanical shutter—a physical curtain that drops in front of the sensor—helps mitigate this on high-end DSLRs. But as we move toward purely electronic shutters (no moving parts), the quality of the sensor readout becomes the only thing that matters.
Notable examples and disasters
The most famous modern example is probably the "Bent iPhone" videos from years ago. Not the ones where people actually bent the phones, but videos where the phone was vibrating on a car dashboard and the whole world looked like it was melting.
Another one is the "Invisible Strings" on guitars. If you film a guitar being plucked in bright sunlight (which forces a high shutter speed), the strings won't look like they're vibrating. They’ll look like weird, undulating waves moving slowly. It’s a perfect visual demonstration of the rolling shutter readout speed versus the frequency of a musical note.
Moving forward with your gear
We are getting better at this. Stacked CMOS sensors—found in cameras like the Fujifilm X-H2S or the Nikon Z9—read data much faster than standard sensors. The "readout speed" is the number to watch. The faster that number, the less distortion you get.
If you’re buying a camera for video, look for reviews that specifically mention "sensor readout speed" or "rolling shutter performance." A camera might have 8K video, but if the rolling shutter is terrible, that 8K is going to look like a wavy mess the second you move the camera.
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Actionable steps to minimize distortion:
- Check your frame rate. Sometimes shooting at 60fps instead of 24fps can slightly reduce the perceived skew because the sensor is being "forced" to read faster to keep up with the frame count.
- Use an ND filter. By using a Neutral Density filter, you can lower your shutter speed. This introduces natural motion blur. While it doesn't "remove" the rolling shutter, the blur smears the distortion, making it look much more natural to the human eye.
- Mind the vibration. If you're mounting a camera to a car, bike, or drone, use a dampener. Even a piece of foam can help absorb the high-frequency jitters that cause the jello effect.
- Embrace the mechanical. If your camera has a mechanical shutter option, use it for high-speed action photography. It solves the problem at the hardware level by blocking the light as the sensor reads.
Rolling shutter is basically a permanent resident in the world of digital imaging. It's a quirk of how we’ve decided to build chips. Unless you’re ready to drop several thousand dollars on a global shutter camera, the best move is to understand how it works and shoot around its limitations. Slow down your pans, stabilize your movements, and maybe don't expect a perfect photo of a spinning airplane propeller.