# What is the shutter speed needed to stop motion?

I find that taking pictures where the subject is in motion (people, pets, toy helicopters) I get a blur where there is movement.

On the other hand I see images of a drop of water in free fall in perfect clarity.

How fast does the shutter need to be to capture action in motion with perfect crisp clarity?

For example I want to catch a dog shaking himself dry after a swim and not get a bury mess but to see the hairs flying and water frozen in the air as it flies off the dogs fur and makes a giant mist around the dog.

• It's impossible to know how long the exposure can be unless you specify the speed at which the subject is moving in the frame. You can use a surprising long exposure if your subject is dripping pitch, but you need a shorter exposure for a speeding bullet. Mar 9, 2016 at 17:54

While you can get some freezing with speeds around 1/300 (see the first photo below), I would recommend going with faster shutter speeds if you want to take shots of water drops falling or moving away from wet dogs.

One thing to keep in mind is that most flashes have a limit on their sync speed, which means that the use of flash will limit your fastest shutter time available.

• Example 1: 1/320 speed, no flash:

(as you see there's still blur on the water and a flash, even if able to reach the dog, wouldn't make much a difference if it wasn't able to go faster than 1/320)

• Example 2: 1/1300 s, using the internal flash of a Panasonic FZ18 and the ambient kitchen light:

Here a smaller aperture and the ambient light allowed for a slight slower speed, but the shot is sharp enough for me.

• Example 3: 1/1600 s, using the internal flash of a Panasonic FZ18, no ambient light (shot in the dark):

Here the speed was enough to freeze the drop and the flash was set stronger enough to provide the needed reflections on the background (since there was no ambient light).

Finally, if you are into capturing water drops don't miss Joanne C's very good post on the subject - Catching the Elusive Water Drop

• +1 though, in your last example, shutter speed doesn't mean much, it's the light that freezes the subject. I do water drop macros all the time using a 1 second shutter speed in a dark setting and the flash is what freezes the drop (usually between 1/16th and 1/64th power). Dec 29, 2010 at 19:28
• Interesting point, never thought that way. Will do the test next time, thanks for the heads up! :o) Dec 29, 2010 at 20:00
• It's fun to do, there's a write up on my website on the technique I use, though I've started using my radio triggers rather than pressing the test button on the flash now, more reliable that way (I use off-camera flash for this). Dec 29, 2010 at 20:31
• Very nice post indeed, added the reference to the answer itself. Thanks a lot! Dec 29, 2010 at 20:46
• @André Carregal - You're quite welcome. Dec 29, 2010 at 21:22

That depends on how fast the object is moving, and how far away it is. From that you can calculate how fast it's image is moving across the film/sensor plane.

It all comes down to having a shutter speed that is so fast that the image of the object doesn't have time to move across too many picture elements (film grains or sensor pixels).

So, for objects at a distance you can get away with a shutter time like 1/100 s., while a closeup might need a shutter time like 1/1000 s.

• In the last paragraph, are you assuming that the focal length doesn't change? It seems to me that two shots where the subject is the same size (i.e. further away but longer focal length) would require the same shutter speed to freeze motion. Dec 29, 2010 at 19:03
• @Evan Krall: Good point. Yes, what I mean is how the object appears in the image, so the focal length of the lens would affect what shutter speed you need. Dec 29, 2010 at 23:18
• +1 for providing quantitative, rather than mere qualitative guidance, and for recognizing that speed of the image on the sensor is what matters. Dec 31, 2010 at 15:51
• Google shutter speed calculator and you'll get for example this calculator - needs some scrolling down the page to find it. Apr 1, 2013 at 8:40

This question can be deterministically answered with a small amount of mathematical calculation. Every sensor has a finite number of horizontal and vertical pixels. Therefore, at any specific focal length, we can determine the effective distance between pixels. The exposure time must be short enough that the moving object does not have sufficient time to travel between pixel during the exposure..

It depends on what you're trying to get exactly, but in general, around 1/500 to 1/1000 is about the right amount, unless it's something really fast. Flash also works really cool for this kind of stuff, as the flash occurs completely in a single instant.

• Flash does not occur in a single instant. Its duration varies between 1/10000 and 1/1000 sec, depending on power.
– che
Dec 29, 2010 at 17:58
• Okay, sure, but that's a short enough time where it doesn't matter a whole lot... Dec 29, 2010 at 17:58
• Not entirely. When dealing with subjects such as water splash macro work, you want the shortest light burst you can get to freeze the motion as longer light bursts will actually result in seeing motion blur in the subject. Dec 29, 2010 at 19:30

It depends on the speed of the object you are photographing.

The distance the object has moved from the time your shutter opens and closes will determine the amount of blur.

So if the object has moved a good distance while the shutter was open it will look quite blurry.

You want the shutter speed to be fast enough so that by the time it opens and closes the object on motion has actually moved so little it appears to be still.