WHAT YOU DON’T KNOW ABOUT SHUTTER SPEED

WHAT YOU DON’T KNOW ABOUT SHUTTER SPEED

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Shutter Speed is one of the three pillars of photography, the other two being ISO and Aperture. Shutter speed is where the other side of the magic happens – it is responsible for creating dramatic effects by either freezing action or blurring motion.

Differences between electronic and mechanical shutters

Electronic Shutter


Silent operation
A key difference is that an electronic shutter is silent, as there is no physical movement of internal parts during exposure. This is useful when the sound of a mechanical shutter being released could affect the subject being photographed i.e. when photographing wildlife close-up, during sports events where you are close to a subject, or somewhere that you want avoid drawing attention to yourself.

Faster frame rate
An electronic shutter has no mechanical parts, which allows it to achieve faster frame rates than a mechanical shutter. i.e. the Nikon 1 V3 camera can shoot 20 fps with an electronic shutter as opposed to 6 fps with a mechanical shutter.

Reduced shake/blur
The movement of a mechanical shutters front curtain or mirror bounce can cause slight vibrations which can display in high resolution cameras as camera shake or blur. When photographing on a tripod with an electronic shutter camera shake or blur are reduced as there is no physical movement inside the camera.

Mechanical Shutter


Rolling shutter distortion reduced
Rolling shutter distortion can be produced with CMOS sensors when recording fast moving subjects with fast shutter speeds or when panning rapidly. With electronic shutters the CMOS sensor is turned On and the sensor scans line by line sequentially and with fast moving subjects rolling shutter distortion can be seen in the image. i.e. the downswing of a golf club in motion. With a mechanical shutter at fast shutter speeds the front and rear shutter curtains are often so close together that essentially only a slit of the image sensor is exposed at once which helps to reduce the effect of rolling shutter distortion.

Faster flash synchronization speeds
Flash synchronization is often faster with mechanical shutters than with electronic shutters. This is due to the characteristics of the electronic shutter and the scan rate of the image sensor. If you are shooting outdoors in bright conditions and you want to use the fastest flash synchronization speed possible then the mechanical shutter is often the best option. i.e. Nikon 1 V3 mechanical shutter maximum flash sync speed is 1/250 sec., whereas the electronic shutters maximum flash sync speed is 1/60 sec.

Shutter SpeedShutter speed is what you want to change when you want to show movement in your picture or when you want to take an incredibly clear shot, a moment in time, without any blur of movement at all.  The slower the shutter speed is, the more movement the camera will capture.

Aperture shutter speed and ISO together are what determines exposure because they both affect how much light is taken in while the picture is being taken.  The most basic definition of shutter speed is how long the shutter takes to open and close.

The shutter is a small “curtain” in the camera that quickly rolls over the image sensor (the digital version of film) and allows light to shine onto the imaging sensor for a fraction of a second. The longer the shutter allows light to shine onto the image sensor, the brighter the picture since more light is gathered.  A darker picture is produced when the shutter moves very quickly and only allows light to touch the imaging sensor for a tiny fraction of a second. The duration that the shutter allows light onto the image sensor is called the shutter speed, and is measured in fractions of a second.  So a shutter speed of 1/2 of a second will allow more light to touch the image sensor and will produce a brighter picture than a shutter speed of 1/200 of a second. So if you’re taking a picture an it is too dark, you could use a slower shutter speed to allow the camera to gather more light.

Just as the aperture affects the exposure as well as the depth-of field, the shutter affects more than just the exposure.  The shutter speed is also principally responsible for controlling the amount of blur in a picture.

Graphic explaining the effects of changing the shutter speed

 

Shutter Speed Measurements

Your shutter speed is measured as the time that the shutter is open. Your camera may be able to keep the shutter open for many minutes and be as quick as just 1/1600 second. Remember that the setting is typically a fraction of a second so the higher the number on the bottom of the fraction the faster the capture and the less light that gets into the camera.

Shutter Priority Mode

If shutter speed means the most to you (which it does in this tutorial) you’ll want to try out the shutter priority mode. The priority modes allow you to do half the work and the camera to do the other half.  In the case of shutter priority mode we’re adjusting the shutter & the camera will adjust the aperture to be sure we have a good exposure. The shortcut for the shutter priority mode is shown as either an “S” or a “Tv” depending on your camera brand.

How to find shutter speed

Do you know how to find out what your camera shutter speed is set to? It is typically very easy to find the shutter speed. On Nikon DSLRs that have a top panel, the shutter speed is typically located on the top left corner:

Nikon D90 Top Panel - Shutter Speed

If you look through the viewfinder, it should also be the number on the bottom left side of the screen. On most DSLRs, you will not see the shutter speed as a fraction of a second – it will typically be a regular number. When the shutter speed is slower than or equals to one second, you will see something like 1″ or 5″ (the ” sign indicates a full second).


minimumShutterSpeedsForMaximumSharpnessInfographic-1

 

THE FOCAL LENGTH VS. SHUTTER SPEED RULE

The simplest answer to how slow of a shutter speed you can use and still get a sharp picture is to use the 1/focal length rule.  The shutter speed/focal length rule says you simply take the focal length you’re shooting at (let’s say 50mm, for an example), and make the denominator in your shutter speed.  Simple!  So if you’re shooting with a 50mm lens, the rule says that you shouldn’t pick a shutter speed slower than 1/50 if you want a sharp picture.  So you could shoot at 1/80 or 1/100 and be just fine, but don’t go to 1/40 or 1/20.

Another example: if you’re shooting at 200mm, the rule says you should not shoot slower than 1/200.  So 1/400 or 1/640 or faster is fine, but don’t choose 1/180 or anything else under 1/200.

There are several issues with taking the 1/focal length rule as the final word on the subject: (1) If you are using a crop sensor camera, do you add the crop factor to the equation?  (2) What about image stabilization, wouldn’t that allow you to achieve a sharper shot at a slower shutter speed? (3) Does the rule break down at very long and very short shutter speeds?  The answer to all three of these questions, is “yes!”

WHY FOCAL LENGTH AND SHUTTER SPEED ARE RELATED

But first, at a basic level, we need to discuss WHY the shutter speed and focal length are related.  I like to think of the example of holding a laser light.  If you get a red laser pointer and point it against the desk in front of you, you can hold the point pretty steady.  You won’t see the point dancing around much.  If you point the laser at a house across the street, no matter how hard you try to hold the laser steady, it will dance around wildly.  You haven’t changed the way you’re holding the laser, and technically you were just as shaky in both situations, but the shake is exacerbated greatly by distance, which multiplies the effect.

When holding a camera, the same thing happens.  A minor shake when shooting wide can’t be seen much because the viewer isn’t zoomed in on the tiniest details.  HOWEVER, when you’re shooting a very long lens, the viewer sees the details and any shake in the camera muffles those details, creating a soft image.

HOW CROP FACTOR AFFECTS THE SHUTTER SPEED RULE

Generally, when photographers talk about different focal lengths, they mean the focal length on a full frame camera.  If you use an APS-C (so called “crop sensor”) DSLR, then you need to multiply the focal length by 1.5 (Nikon, Fuji, or Sony crop sensor) or 1.6 (Canon crop sensor) in order to get the equivalent focal length.  So a 50mm lens, when put on a full frame camera is 50mm.  But when it’s put on an APS-C sensor, has the equivalent focal length of about 75mm.

That may leave you wondering why, in the chart above, the numbers for crop sensor are all lower than those in the full frame columns.  The reason is the field of view, which is the number we need for the proper calculation above.  In that scenario, we are not saying that the same lens is put on both cameras, but it is trying to show what focal lengths produce the same field of view, and what shutter speeds can be used at those focal lengths to produce a sharp image.

If you forget about the chart and want to just do the calculation on your own for the 1/ focal length rule, then you would first figure out the equivalent focal length, and then use the rule normally.  So if your lens is zoomed to 40mm, you would need a shutter speed not of 1/40 (which is the rule for a full frame shutter speed calculation).  You would multiply 40mm x 1.5 (the crop factor for your crop sensor) and get an answer of 60.  Now apply the 1/focal length rule and you know you need a shutter speed of at least 1/60.

If you don’t want to do that calculation every time, just use the chart above.  I’ve done the hard work for you.  But also, don’t turn sharpness into a math problem.  The 1/focal length rule is a GENERAL rule and is not at all a perfect science.  It just gives you a starting place.

This is a 100% crop from some of the photos I took as I was testing this out for the chart above. I taped a piece of paper to the fence and took pictures of it. The lettering on the paper makes judging sharpness easy. You may be tempted to say that only the picture on the left is "sharp enough for your standard." But remember that these are zoomed in all the way. If you're viewing the first three photos at a normal size on the web, you couldn't tell the difference at all between them.

THIS IS A 100% CROP FROM SOME OF THE PHOTOS I TOOK AS I WAS TESTING THIS OUT FOR THE CHART ABOVE. I TAPED A PIECE OF PAPER TO THE FENCE AND TOOK PICTURES OF IT. THE LETTERING ON THE PAPER MAKES JUDGING SHARPNESS EASY.
YOU MAY BE TEMPTED TO SAY THAT ONLY THE PICTURE ON THE LEFT IS “SHARP ENOUGH FOR YOUR STANDARD.” BUT REMEMBER THAT THESE ARE ZOOMED IN ALL THE WAY. IF YOU’RE VIEWING THE FIRST THREE PHOTOS AT A NORMAL SIZE ON THE WEB, YOU COULDN’T TELL THE DIFFERENCE AT ALL BETWEEN THEM.

SHARPNESS MEANS DIFFERENT THINGS IN DIFFERENT SITUATIONS (TO DIFFERENT PEOPLE!)

The chart above, and generally how photographers talk about sharpness is as if there are only two options: sharp, and blurry.  That’s not really the case.  Sharpness is a range.  The 1/focal length rule gives you an approximation for the slowest shutter speed you can go to and still get a reasonably sharp image about 80% of the time.  You’ll still take some blurry shots if you’re at the minimum.  But the more interesting question is–what constitutes a “sharp” photo?

If I were taking a photo that I knew was going to be printed huge, or which I was going to later crop, I would have a very different standard for sharpness than some other photos, because I’ll be zooming in to see the little details.

Further, as cameras increase in resolution, the standard for sharpness only increases.  Only a few years ago when I started to do photography professionally, I was shooting on a 10 megapixel DSLR.  Now, DSLRs commonly shoot 24 to 36 megapixel images–and higher!  Since we’re able to capture more fine detail, the tiniest softness in detail will be visible on the image, so the standard for sharper and sharper images has gone up dramatically.

If you’re shooting mission-critical images where you know sharpness needs to be perfect, do NOT shoot right at the 1/focal length rule.  You’ll want to click a little further on the shutter speed wheel.

What is a Shutter Release

It’s a (wired or wireless) button to release the shutter. There are a couple of times they’re useful. One is for things like shooting wildlife in a situation where you can set the camera up close to a likely spot, and trigger it remotely when a good target walks/flies/swims/whatever into its field of view.

Another is when you want to minimize camera shake for longer exposures, when pushing the button on the camera itself would tend to shake the camera a bit, but little or no vibration is transmitted to the camera by a remote release.

How do DSLR shutters work?

When it comes to a DSLR camera shutter there are 3 basic mechanisms: the mirrorbox, the bottom door, and the top door. When you look through a DSLR view finder you are essentially looking through a series of mirrors that get their light directly from the lens. When you click the shutter button that system of mirrors flips upwards to allow light to pass to the sensor. This is why the viewfinder goes black for a short amount of time when taking photos.

Once the mirror is flipped upwards a small door will move from top to bottom exposing the sensor beneath. After that another door will fall down, covering up the entire sensor. This process can vary in time depending on the length of your shutter speed. Sometimes a shutter speed can be so fast that your camera sensor won’t be entirely exposed at any one time.

After the second door closes your mirror will fall back into place. The doors will then reset to their original positions underneath. This entire process from mirror up to mirror down is known as an actuation. A typical DSLR can withstand over 100,000 actuations in its lifetime.

The following is a graphic example of 1 full actuation:

Shutter Example

How do mirrorless camera shutters work?

Unlike DSLRs, mirrorless cameras don’t use a mirror box or pentaprism to project light directly into the viewfinder. Instead, when using a mirrorless camera the sensor is perpetually exposed to incoming light by default with nothing in-between. This is why mirrorless cameras use either an LCD screen or an electronic viewfinder to monitor what is coming through the lens.

As soon as the user hits the shutter button a door will swing up to cover the sensor. Once covered up the sensor will begin exposing. The door will then swing down to expose the sensor to light. After that another door will swing down to cover the sensor. The sensor will then stop exposure and the doors will reset.

Here’s an example of how a mirrorless camera works:

Mirrorless Shutter Example

Why do cameras have mechanical shutters anymore?

Before the existence of digital sensors it was vital your camera have a mechanical shutter. This is because you can’t simply turn film on or off like a digital sensor. Pre-developed film is light sensitive, meaning any exposure to outside light would severely damage your images. However, in the age of digital photography the landscape is certainly different. Modern sensors are fully capable of taking photographs without a mechanical shutter.

iPhone CameraImage from Shutterstock

Smaller consumer cameras like point-and-shoots and phone cameras are all examples of shutterless cameras. Shutterless cameras tend to have more image noise in the image than their traditional shuttered counterparts. This is because shutterless cameras constantly send power to the sensor. When a user hits the shutter button the sensor is flooded with more power and the image is captured and if you’re familiar with ISO you know that more power equals more noise.

We will likely see professional shutterless cameras in the future, but for now they simply are too grainy/noisy for most high-end professional photography.

How do shutters work when capturing video?

When shooting video on a the shutter process is much different. Because a typical still camera can only activate it’s shutter mechanism about 6 times per second, the physical shutter doors are far too slow to shoot video (which is typically shot in 24 or 30 fps). Instead, when shooting video or in the live-view mode your shutter doors and mirror are left open, leaving your sensor perpetually exposed. Instead of relying on mechanical processes, the ‘shutter speed’ when shooting video is only a reference to a timed amount of power that goes through the sensor. This is known as an electronic shutter. After each frame is captured the electronic shutter resets.

What is a global shutter?

Although the name would insinuate that it is simply a type of shutter process, a global shutter is more a camera sensor related feature. When it comes to camera sensors there are two main categories that you need to know CMOS and CCD.

CMOS sensors are more common among consumer to pro-sumer cameras, but they are also more problematic. This is because CMOS sensors read pixel information from the top left of the sensor to the bottom right. This is a problem because if your subject is incredibly fast and moves position during capture you will get warped images. This is known as rolling shutter and it can produce some pretty annoying ‘jello’ effects, especially when shooting video.

Rolling vs Global Shutter
Image from Andor.com

On the other hand CCD sensors, or global shutters, will record the entire frame at once, very similar to a film camera. This eliminates warping, leaving you with a more pleasing image.

What is a rotary disk shutter?

Rotary disk shutter only pertains to actual film (movie) cameras. As you probably already know, a film camera works by exposing 24 individual film frames to light per second. The result is fluid motion that gives the illusion of movement. As you can imagine, the mechanical processes already covered in this article, known as focal-plane shutters, are far too complex and time consuming to be performed 24 times per second. Instead a film camera uses a rotary disk shutter.

This shutter looks very similar to a fan. In short, the Rotary Disk rotate on the inside of the camera body, exposing the film to light then covering it up again with the blade of the disk. The rotary disk process works in 3 steps: under the cover of the disk the camera film would move into place, the disk would allow light in, and the disk would cover the frame. Repeat this process 24 times per second and you have yourself a moving picture.

Shutter Angle via Wikipedia
Image from Wikipedia

The thing that makes rotary disk shutters truly unique is the way in which the shutter speed is calculated. In modern cameras you can select the exact shutter speed you want for your image, but in traditional film (movie) cameras you have to calculate your shutter speed yourself. Rotary disks have the shutter angle, or the size of the pizza slice (see chart), listed on their blades. DP’s can then go in and determine what the shutter speed is by calculating the shutter angle with the frame rate.

For example, if you were shooting a film at 24 fps and had a rotary disk with a shutter angle of 180 degrees your shutter speed would be 1/48 or double 24 fps. The following diagram may help you get a good idea of how this process works.

Shutter Angle Example

If you are looking to shoot on film in the near future there are a lot of really good online resources to help you figure out your shutter speed. It’s also not uncommon to see shutter speed displayed by shutter angle when shooting on high-end cinematography cameras.

What in the heck is a leaf shutter?

A leaf shutter is a shutter that functions inside of a lens. Instead of acting like a door or a fan, a leaf shutter works a lot like a lens aperture.

Leaf Shutter in ActionImage from KernPhoto

You won’t find leaf shutters in everyday cameras. Typically they are only found in medium format high-end photography cameras. They can function at higher flash sync speeds (up to 1/1600) making them great for anyone who wants to shoot outdoors at a low f-stop with a strobe. Because these lenses are hand crafted, not manufactured on an assembly line, they tend to be incredibly expensive.

SHUTTER SPEED FOR EVERY SITUATION

Freeze Movement – 1/250sec and faster

Common mistakes at every shutter speed

Static-looking shots
With all the movement frozen, fast shutter speed shots can look too static. You can try tilting the camera for a more dynamic photo composition, but the best option is usually to use a panning technique.

Common mistakes at every shutter speed

Blurred shots
If you have unwanted blur, then the subject was either out of focus, or it was moving too fast for the shutter speed.

Check that the subject hasn’t moved from your AF point. If the blur is down to subject movement, you’ll need a faster shutter speed.

Suggested shutter speeds for freezing action

  • Fast-moving cars, motorbikes or animals: 1/1000sec
  • Mountain bikes: 1/500sec
  • Waves: 1/250sec

What you can do
Shooting as many frames as possible isn’t always the best approach. Instead, try to shoot in short bursts when the action is at its peak.

This provides the best chance of capturing the best images, while allowing the camera enough time to write the images to your memory card without locking up.

Blur Action – 1/15sec to 1/250sec

Common shutter speed problems: too much movement

Too much movement
If everything is blurred in your shot, try using a faster shutter speed that will capture the subject sharply.

If this freezes all the action then the subject isn’t staying in the same position in the frame. This is where your new panning techniques come into play.

Common shutter speed problems: not enough movement

Not enough movement
If there isn’t enough blur in the background you need to use a slower shutter speed, otherwise your moving subject will look static.

If your shooting situation allows, you should try to alter the speed in small steps so that you can still get the main subject sharp.

Suggested shutter speeds for panning

  • Fast-moving cars, motorbikes or birds: 1/125sec
  • Mountain bikes close to the camera: 1/60sec
  • Mountain bikes, moving animals or running people: 1/30sec

What you can do
Using a burst of flash is a great way of ensuring that your subject is sharp when shooting subjects such as cycling and motocross.

It’s only useful when you can get close to the subject, though, so don’t expect it to make a difference to subjects such as motor racing if you’re a long way from the action.

Creative Blur – 1/15sec to 1sec

Common shutter speed problems: overexposure

Over-exposure
At slow shutter speeds, it’s easy for areas subject to large amounts of movement, such as the sea, to create over- exposure.

Take a test shot at the suggested settings and take a look at the histogram (or highlight warning) display to make sure the highlights are correctly exposed.

Suggested shutter speeds for blurred motion

  • Fast-flowing waterfall: 1/8sec
  • People walking close to the camera, or waves and slow-moving water: 1/4 sec

What you can do
In bright conditions you may find it difficult to get your shutter speed below 1/8 sec, even using the smallest aperture and lowest ISO settings.

Fitting a polariser filter onto the front of your lens is a great way of reducing the amount of light reaching the sensor, allowing you to reduce the shutter speed by half or more.

Long Exposures – 1sec to 30secs

Common mistakes at every shutter speed

Camera movement
Even with the camera mounted on a tripod it can still move, causing the image to blur. In windy conditions, try weighing down the tripod with your camera bag to minimise the movement.

It’s also worth checking that the feet of the tripod are on solid ground.

Suggested shutter speeds to blur movement

  • Moving foliage in gentle wind: 30secs
  • Traffic trails: 20secs
  • Smooth seas: 15secs
  • Fast-moving clouds: 8secs
  • Waves, retaining some detail: 1sec

What you can do
If you’re shooting before sunrise or after sunset, the light levels will change quite rapidly. So you’ll have to set a smaller aperture (or use a faster shutter speed) as dawn approaches, or as it gets darker after sunset you’ll need to use a larger aperture (or decrease the shutter speed).

 

Night Photography – 30secs or longer

Common mistakes at every shutter speed

Hot pixels
Shooting long exposures can also result in hot (or stuck) pixels. These are individual pixels that appear much brighter than those around them due to their response to light.

Using the long-exposure noise reduction feature helps to reduce the visibility of these in your image, but you can also remove them using the Healing Brush in Photoshop.

Suggested shutter speeds for night exposures

  • Movement just visible in stars, or full moon-lit landscapes: 2 minutes
  • Distinct star trails: 10 minutes

 

If you find it helpful, comment below and let us know what you need to learn next.