Rolling Shutter vs Global Shutter: Sensor Readout Modes

How electronic shutters work

All digital cameras capture an image by exposing a sensor to light and then reading the accumulated charge from millions of photodiodes. The way that readout happens defines whether a camera has a rolling shutter or a global shutter. With a rolling shutter, the sensor resets and reads rows of pixels in sequence, usually from top to bottom. With a global shutter, every pixel row captures light simultaneously, and the entire frame is read out at once after the exposure ends.

Mechanical shutters physically open and close in front of the sensor, but many modern cameras, especially mirrorless cameras, offer an electronic shutter mode that performs the entire exposure and readout without moving parts. If your camera has an electronic shutter option, it almost certainly uses a rolling readout unless the manufacturer explicitly states it uses a global shutter. Shutter types determine which mode you can use and what limitations apply.

Rolling shutter artifacts: skew, jello, and banding

Because a rolling shutter captures different rows at different moments, any movement that happens during the readout appears distorted in the final frame. The three most common artifacts are skew, jello, and banding.

Skew happens when a fast-moving subject slants sideways: a vertical pole or a car's wheel can appear tilted because the top of the subject is recorded earlier than the bottom. Jello effect is a wobble that appears in handheld video when the camera shakes during the readout. Banding occurs when the sensor rows are exposed at different points in the cycle of artificial lighting; under LED or fluorescent lights, horizontal stripes can appear across the frame. The slower the sensor readout, the more visible these artifacts become.

The readout speed of a rolling shutter is not a fixed number: cheaper sensors read more slowly than high-end ones. A high-end camera with a very fast readout can show almost no skew in normal use, while a budget camera with a slow readout may show obvious slant even with moderate subject motion. You cannot fix rolling shutter artifacts in post, so choosing a camera with a fast sensor readout matters if you photograph sports, wildlife, or anything that moves quickly.

Global shutter advantages

A global shutter exposes every pixel at the same instant, so it completely eliminates skew, jello, and banding. This has been a long-standing requirement for cinema cameras, industrial machine vision, and scientific imaging, where a distorted frame would be useless. In recent years, global shutter sensors have appeared in a small number of consumer and prosumer cameras, mostly in the mirrorless and cinema space.

The tradeoff with a global shutter is complexity. A global shutter sensor needs a storage area for the charge of every pixel, which increases sensor size, power consumption, and manufacturing difficulty. Early global shutter sensors had lower dynamic range and higher noise than comparable rolling shutter sensors, though that gap has narrowed with newer designs. For the majority of photo buyers, the global shutter price premium is hard to justify. Still, if you shoot professional video, fast sports, or any subject with rapid motion, a global shutter is worth the extra investment.

If you are looking for a camera with a global shutter or a very fast rolling shutter, check the sensor readout spec in the datasheet or the manufacturer's own specification page. The maker's page will state whether the sensor uses a global shutter or a rolling shutter, and it will list readout speed if that is a marketing point.

Which readout mode should you choose?

The honest answer is that most stills photographers do not need a global shutter. If you shoot landscapes, portraits, architecture, or product photos on a tripod, a rolling shutter will not affect your results, because nothing in the frame moves during the readout. If you shoot 4K video or 8K video, the sensor readout is done continuously, so rolling artifacts become much more visible, especially when you pan the camera or when your subject moves quickly through the frame.

Action cameras, which are often mounted on moving vehicles or worn on helmets, have traditionally been the worst offenders for rolling shutter skew. Many new action cameras now include a global shutter or an electronic mode that does a fast enough readout to hide most artifacts. If you shoot action video, a global shutter is a real benefit. For general video on a standard mirrorless camera, a rolling shutter is acceptable, but you should be aware of its limits.

If you work under artificial lighting, you can often avoid banding by setting your shutter speed to a multiple of the local power line frequency (for example, 1/60 or 1/120 second in North America, 1/50 or 1/100 in Europe). This does not fix skew or jello, but it addresses the most annoying flicker artifact. If you cannot avoid banding with your camera's shutter speed options, a global shutter is the reliable fix.

Where the market is heading

Global shutter technology is no longer exclusive to high-end cinema cameras. A handful of consumer cameras from Sony and other brands now include global shutter sensors, and the cost of the technology is expected to keep dropping. In the meantime, rolling shutter sensors continue to improve: high-end mirrorless cameras read out their sensors so fast that skew is barely visible even with fast-moving subjects.

The decision is about whether the artifacts matter for your use. If you shoot sports, wildlife, or any fast action, look for a camera with a very fast sensor readout or a global shutter. If you shoot video professionally, a global shutter is a strong advantage. For everyone else, the convenience and low cost of a rolling shutter camera is the right call. If you are unsure, compare the sensor readout specs on the cameras you are considering and check the manufacturer's own technical pages.

If you are ready to compare specific video cameras or high-resolution models, read the spec sheets carefully. A camera that lists a global shutter is immediately worth more for action and video work. A camera that only lists a rolling shutter can still be excellent, as long as you work within its limits.

What to pick for your use

Questions

What is the difference between a rolling shutter and a global shutter?

A rolling shutter exposes and reads the sensor line by line, while a global shutter exposes the full frame at once. This means a global shutter creates no skew, jello, or banding artifacts, but it costs more to manufacture.

Do all cameras use a rolling shutter?

No. Most consumer cameras use a rolling shutter, but some cinema cameras, industrial cameras, and a growing number of high-end mirrorless and action cameras use a global shutter.

Can I fix rolling shutter artifacts in post-production?

Some software can partially correct skew, but jello and banding are very difficult to fix. The cleanest solution is to choose a camera with a global shutter or a very fast rolling shutter readout.

Why do some cameras have a mechanical shutter if electronic shutters are available?

A mechanical shutter prevents rolling artifacts because it physically covers the sensor all at once. Many photographers use the mechanical shutter for stills when they want no electronic artifacts, and use the electronic shutter for silent shooting or video.

Does a global shutter affect image quality?

Early global shutter sensors had lower dynamic range and more noise, but newer designs have improved. The image quality difference is now small on high-end sensors, though global shutter sensors tend to cost more and use more power.

What is the best shutter mode for video?

For video, a global shutter is ideal because it eliminates skew and jello. If your camera only has a rolling shutter, use a fast readout mode if available, and avoid fast panning to reduce visible artifacts.