Mechanical vs Electronic Shutter: Which Should You Use?

A mechanical shutter uses two physical curtains that cross the sensor in a few thousandths of a second. An electronic shutter has no moving parts and reads the sensor row by row, which on most cameras takes far longer. Use mechanical or electronic first curtain for flash, fast action and flickering artificial light. Use the electronic shutter when you need silence, zero vibration or speeds beyond 1/8000 second, and nothing in the frame is moving quickly.

The glossary entries for the mechanical shutter and the electronic shutter define each type on its own. This page compares them side by side: what each one physically does, the three failure modes of electronic readout (skew, banding and flash trouble), the two failure modes of moving curtains (vibration and noise), the hybrid electronic first curtain setting, and a table of which mode to choose for which situation.

The three shutter modes in your menu

Most mirrorless cameras offer three choices under a menu item called something like shutter type. The names vary, but the mechanisms are the same.

• Mechanical. Curtains start and end the exposure.
• Electronic first curtain. The sensor starts the exposure electronically and a mechanical curtain ends it. Often abbreviated EFCS, or called electronic front curtain.
• Electronic. The sensor starts and ends the exposure with no moving parts. Often labelled silent shutter or silent shooting.

The exposure is identical in all three: 1/250 second at a given aperture and ISO gives the same brightness whichever mode times the shutter speed. What changes is how long the whole frame takes to record, and whether anything physically moves.

Curtain travel time: the number that defines a mechanical shutter

A focal-plane shutter has two curtains made of thin blades. The first curtain uncovers the sensor, the second covers it again, and the gap in time between them is the shutter speed. The curtains do not move faster at faster shutter speeds. They always cross the sensor at the same pace, typically in something like 1/250 to 1/400 second. To get 1/4000 second, the second curtain simply sets off almost immediately after the first, so that a narrow slit sweeps down the sensor.

Two consequences follow. First, there is a fastest speed at which the whole sensor is uncovered at once. That is the flash sync speed, commonly between 1/160 and 1/250 second. Second, even a mechanical shutter records the top and bottom of the frame at slightly different moments at fast speeds. The difference is only a few milliseconds and almost never shows.

The costs of curtains are physical: noise, wear (see shutter count), a top speed of about 1/4000 or 1/8000 second, and a slight jolt each time they start and stop.

Readout time: the number that defines an electronic shutter

With an electronic shutter the sensor does the timing. Each row of pixels is cleared, allowed to collect light for the set shutter speed, then read. The rows cannot all be read at the same instant, so the camera works down the sensor one row after another. This is rolling readout. Each row gets the correct exposure, but the last row starts and finishes later than the first.

How much later is the readout time, and it is the single most useful number for understanding the electronic shutter. On many conventional sensors a full-resolution still takes somewhere between about 1/15 and 1/60 second to read, and some high-resolution sensors are slower still. Stacked sensors, which put fast memory and circuitry directly behind the pixels, cut this to roughly the pace of a mechanical curtain.

Compare the two numbers: a mechanical curtain crossing in about 1/300 second and a typical electronic readout taking about 1/20 second. The electronic shutter is around fifteen times slower at getting from the top of the frame to the bottom, and every weakness it has comes from that gap. A global shutter sensor closes the gap completely by ending the exposure for every pixel at the same instant, at some cost in sensor performance, and it is still uncommon in stills cameras.

Skew: why a faster shutter speed does not help

If the subject or the camera moves sideways while the sensor is being read, each row records the subject in a slightly different place. Upright things lean, round wheels become ovals, and spinning things bend. The page on rolling shutter distortion shows the range of effects; here is how to predict them.

The lean equals the distance the subject travels across the frame during the readout. Shutter speed does not enter into it. A faster shutter speed makes each row sharper, but the rows are still recorded at different times, so the subject is sharp and bent instead of blurred and bent.

A worked example. A car passing at 100 km/h covers about 28 metres per second. With a 1/20 second readout, the car moves 1.4 metres between the top row and the bottom row of the frame. If the car fills half the frame height, its roof and its tyres are offset by about 70 centimetres, an obvious slant. With a mechanical shutter crossing in 1/300 second the same car is offset by less than 5 centimetres over that half frame, which nobody will notice.

Where skew shows and where it does not

• Shows badly: propellers and rotor blades, golf clubs, bats and racquets mid-swing, vehicles passing close, fast panning past posts or buildings, and anything shot from a moving vehicle with upright objects near the road.
• Does not show: subjects moving toward or away from you, slow subjects, distant subjects that cross only a small part of the frame during the readout, and anything still.

Propellers are the hardest case. An aircraft propeller may turn 40 times a second, so during a 1/20 second readout it completes two full turns, and the blades are drawn as detached curved shapes.

Banding under artificial light

Many artificial lights pulse 100 or 120 times a second. A frame that takes 1/20 second to read spans five or six of those pulses, and each dim moment is recorded as a dark stripe across the rows being exposed at that instant. A mechanical shutter crossing in 1/300 second spans less than half a pulse, so at worst you get a soft gradient or a frame that is a little brighter or darker than the last one.

The guide to flicker and banding under artificial light covers light sources, safe speeds and anti-flicker modes. For this decision, three points matter:

• The stripes run along the sensor rows, across the long side of the frame in landscape orientation, and they shift position from frame to frame.
• A flicker-safe shutter speed works in every mode. If each row is exposed for a whole number of pulses, every row gets the same light, however slowly the rows are read. Electronic shutter at 1/50 or 1/100 second on a 50 Hz supply, or 1/60 second on a 60 Hz supply, is usually clean.
• Some LED lights pulse thousands of times a second. Dimmed stage lights, video walls and some signs do this. They can leave many fine stripes with the electronic shutter that no standard shutter speed removes. Some cameras offer a fine shutter-speed adjustment for exactly this; otherwise switch to mechanical.

Flash: what each mode can and cannot sync

A flash burst is very short, often well under a thousandth of a second (see flash duration). For the whole frame to be lit, every row of the sensor must be collecting light at the moment the flash fires.

• Mechanical. Flash works at any speed up to the sync speed. Above it, the slit hides part of the sensor when the flash fires and you get a dark bar, unless you use high-speed sync, which pulses the flash for the whole curtain travel at reduced power.
• Electronic first curtain. Flash generally works as it does with the mechanical shutter, up to the same or a similar sync speed. This is the normal choice for flash on many mirrorless cameras.
• Electronic, rolling readout. All rows are only exposing together if the shutter speed is longer than the readout time. With a 1/20 second readout that would mean flash only at about 1/15 second or slower. For that reason many cameras simply disable flash in electronic shutter mode, and others allow it only at a slow sync speed. Stacked sensors with fast readout can sync at more useful speeds. Check your manual for the exact limit.
• Global shutter. Every pixel starts and stops together, so flash can sync at any shutter speed, although an exposure shorter than the flash burst itself cuts off part of its light.

There is a second flash problem that catches people at weddings and press events: other people’s flashes. If a guest’s flash fires while your electronic shutter is partway through its readout, only the rows exposing at that instant are lit, and your frame gets a bright horizontal band.

Electronic first curtain: the hybrid and its two side effects

In electronic first curtain mode the mechanical shutter stays open before the exposure. The sensor begins collecting light row by row in a sweep timed to imitate a curtain, and the real second curtain then travels across to end the exposure. The frame is recorded as quickly as with a fully mechanical shutter, so skew and banding behave as they do in mechanical mode.

The gain is that nothing moves just before or during the start of the exposure. That removes shutter shock, shortens the delay between pressing the button and the exposure starting, and roughly halves the noise.

The side effects appear only at fast shutter speeds combined with wide apertures:

• Clipped bokeh. The electronic “curtain” is on the sensor surface itself, while the mechanical second curtain sits a few millimetres in front of it. At slow speeds this does not matter. At very fast speeds the slit is narrow, and the two edges of the slit are at different depths. Light arriving at steep angles from the edges of a wide aperture is partly blocked. Out-of-focus highlights lose a slice from one side, so round discs look cut off, and the background blur becomes a little busier. See bokeh for what smooth blur depends on.
• Uneven exposure. The same geometry can make one edge of the frame slightly darker than the other, a gentle gradient from top to bottom.

Both effects grow as the shutter speed gets faster and the aperture gets wider. As a rough guide, they are worth watching for from about 1/1000 or 1/2000 second upward at f/2 and wider, and they are hard to find at f/4 or slower lenses. Many cameras deal with this for you: an automatic shutter mode uses electronic first curtain at ordinary speeds and switches to full mechanical above a threshold. If yours does not, switch to mechanical yourself when shooting a fast lens wide open in bright light.

Shutter shock: when the curtains blur the picture

In full mechanical mode on a mirrorless camera, the shutter has to snap closed and then open again to begin the exposure. That first curtain stopping is a small impact, and the exposure starts while the body is still ringing from it. The result is a slight softness or a faint double edge on fine detail. The camera shake guide covers the other causes of the same look.

Shutter shock has a characteristic range. It is usually worst at moderate speeds, somewhere around 1/30 to 1/250 second. Faster exposures are over before the vibration has moved the image much, and exposures of a second or more are long enough that the brief vibration is a tiny fraction of the total. It is more visible with long focal lengths, high-resolution sensors and close-up work. A tripod does not cure it, because the vibration starts inside the camera.

Either electronic mode cures it. Electronic first curtain removes the impact before the exposure. The fully electronic shutter removes every moving part, which makes it the best option for tripod work with static subjects: landscapes, architecture, product shots, copy work and macro stacks.

Silent shooting: when the trade is worth it

Silence is the reason most people first turn on the electronic shutter. It is the right call when the sound would cost you the picture or disturb people, and the subject is not moving fast.

• Good uses: ceremonies and speeches, quiet music, theatre where cameras are permitted, film sets, sleeping children, nervous animals at rest, candid street scenes, and museums and churches.
• Check first: any venue lit by LEDs or fluorescent tubes. Take a test frame at your working shutter speed and inspect it at full magnification for stripes before the event starts.
• Poor uses: anything with flash, sport, and birds in flight unless your camera has a fast-readout sensor.

The electronic shutter also extends the top of the shutter speed range. On a sunny day at ISO 100, a correct exposure at f/1.4 needs about 1/12800 second. A mechanical shutter that stops at 1/8000 overexposes that by two thirds of a stop, and one that stops at 1/4000 by more than a stop and a half. The electronic shutter reaches the speed without a neutral density filter, and a still subject shows no side effects.

Which setting for which situation

The table assumes a typical sensor with a slow readout. With a stacked or global shutter sensor, electronic is safe in far more of these rows.

Common mistakes

Leaving silent mode on after the quiet event. The next day’s cycling race or flash portrait comes out bent, striped or with the flash refusing to fire. Fix: put shutter type in your quick menu or on a custom button, and reset it when you pack the camera away.

Raising the shutter speed to cure skew. The subject gets sharper but stays slanted, because the lean depends on readout time, not exposure time. Fix: switch to mechanical or electronic first curtain, or reduce how fast the subject crosses the frame.

Blaming the lens for nervous bokeh at fast speeds. Out-of-focus highlights with a flat edge at f/1.4 and 1/4000 second are a first curtain effect. Fix: use the full mechanical shutter, or the camera’s automatic shutter mode, for wide apertures in bright light.

Shooting silently under unknown lights without a test. Stripes are easy to miss on a small rear screen. Fix: take one frame, zoom to full magnification, and scroll from top to bottom before the event begins.

Try this

Measure your own camera’s behaviour in about 15 minutes. You need a room with a ceiling fan or a desk fan, and one mains-powered LED or fluorescent light.

1. Set shutter priority or manual at 1/1000 second with auto ISO. Photograph the spinning fan in mechanical mode, then electronic first curtain, then fully electronic. Compare the blade shapes. Straight blades in the first two and curved or thickened blades in the third show you your readout skew.
2. Point the camera at a plain wall lit only by the LED or fluorescent light. Shoot at 1/1000 second in mechanical mode, then electronic. Count any dark stripes in the electronic frame. Under 100 Hz flicker, five stripes mean a readout of about 1/20 second; ten stripes mean about 1/10 second. Under 120 Hz flicker, six stripes mean about 1/20 second.
3. Still in electronic mode, change to 1/50 or 1/60 second (whichever matches your mains supply) and shoot the wall again. The stripes should vanish.

No stripes in step 2 probably means the light is steady, not that your camera is immune. Try a different lamp.

Frequently asked questions

Is image quality different between mechanical and electronic shutter?

For a static subject in steady light, the files are effectively the same: same sensor, same exposure, same lens. The exceptions are cameras that reduce raw bit depth in electronic mode, which slightly reduces how far shadows can be lifted, and the motion and flicker artefacts described above.

Should I leave electronic first curtain on all the time?

For most people, yes, or use the automatic shutter mode if the camera has one. It removes shutter shock and has no drawback at ordinary shutter speeds. Switch to full mechanical only for very fast shutter speeds with a wide-aperture lens, where bokeh can be clipped and exposure can become uneven.

Why are there stripes in my photos with silent shutter?

The lights are flickering and the sensor is being read too slowly to hide it. Each dark stripe is a moment when the light was dim. Use a shutter speed that matches the mains frequency, such as 1/50 or 1/100 second on a 50 Hz supply or 1/60 second on a 60 Hz supply, or switch to the mechanical shutter.

Can I use flash with an electronic shutter?

With electronic first curtain, yes, at the normal sync speed. With a fully electronic rolling shutter, many cameras disable flash and others limit it to a slow shutter speed, because the sensor takes too long to read. Cameras with very fast readout or a global shutter are the exception.

Related guides

• Rolling shutter: what skew, wobble and bent blades look like in stills and video.
• Flicker and banding under artificial light: flicker-safe speeds and anti-flicker modes in full.
• Flash sync speed: why the curtains set an upper limit for flash.
• Camera shake: telling shutter shock apart from hand movement and fixing both.
• How image sensors work: what happens in each pixel during exposure and readout.
• Mirrorless vs DSLR: how the shutter and viewfinder differ between the two designs.