I thought it was time to write another brief tutorial for those that have just got a new DSLR, or are experimenting with a new point and shoot that gives you a higher degree of control over your exposure. In my previous tutorial I gave an overview on aperture, giving you an idea of how it’s use will impact your exposure. And during that overview we learned that exposure is influenced by three primary factors – aperture, shutter speed, and ISO. This post will focus on shutter speed.
Shutter speed is measured in seconds; more often than not it’s measured in fractions of a second. You may see shutter speed expressed as a whole number (5″, which means 5 seconds) or as 1/250 (which means one two hundred fiftieth of a second – fairly fast). Fractions were never my strong point, so remember that 1/500 is slower than 1/1000. When you look at this value on a camera, the shutter speed number will just be the denominator (bottom number) of the fraction. In the picture below, the 4.0 is the aperture (or f/stop) and the 30 on the left is the shutter speed which actually means 1/30 second. If it was 30 seconds it would have the quotation symbol beside it (30″).
This value is giving you an indication of how long the shutter is open, which has an impact on the amount of light hitting the sensor. So given a consistent aperture and ISO, the shutter speed will allow you to creatively alter the exposure of your photo. Shutter speed values range from 1/8000 sec in pro range cameras (and believe me, that is FAST) to usually 30 seconds on the long end. For exposures longer than 30 seconds the camera needs to be set to Bulb mode. This is a mode where the shutter effectively stays open while the shutter-release button is held down, and can theoretically be open for any amount of time.
Now as Dr. Who would tell you (sorry if that reference is lost on you), playing with time can carry some risk. There is one fundamental thing that the shutter speed will profoundly impact in your photography, and that’s motion. This can manifest itself in various ways; it can make your photos sharp and capture an instant of movement, or it can allow you to blur the motion of an object. So let’s see it in action.
Below I’ve taken a series of photos of my “nifty fifty” lens. I set it up on a dresser and let it roll, giving it a slight nudge to get it moving at the same pace for each picture. I selected an assortment of shutter speeds and snapped pictures of this rolling lens to show how the image is impacted by the shutter speed.
Looking at the image above it’s tough to even tell what this is. You can easily deduce that it’s moving and the blur is obvious.
The above photos is taken at 1/15 of a second. You can now make out that this is a lens and if you knew camera brands you could probably tell that it says Canon on the lenscap (although now that I say that it would be pretty tough).
Okay – at 1/60 sec we’re getting somewhere. You can now definitely make out the Canon on the lenscap and you can tell there’s something written on the outside edge of the lens as well.
Finally, our closing picture shows the lens pretty clearly. If you’re a real pixel peeper you’ll notice that it’s not perfectly sharp but this isn’t far off the mark. If you went a little bit faster, say to 1/500, you would have a perfectly clear picture and wouldn’t be able to tell that it’s moving. (That being said, I don’t think many can tell that the above is moving either).
Now – similar to aperture, shutter speed also has particular points that are identified as stops. The table below gives you an idea of these stops:
1 sec ½ sec ¼ sec 1/8 sec
1/15 sec 1/30 sec 1/60 sec 1/125 sec
1/250 sec 1/500 sec 1/1000 sec
For those of you math wizards out there, you’ll notice that each of these numbers is (approximately) half that of the previous (or twice as much, depending on which direction you’re moving). You can also refer to each of these moves as a “stop” – so moving your shutter speed from 1/30 sec to 1/8 sec is two stops. Moving from 1/125 to 1/250 is one stop. As with aperture, this doesn’t mean that the table above contains the only shutter speeds available to you. For example between 1/125 and 1/250 you’ll have 1/160 (which is 1/3 stop), 1/200 (which is 2/3 stop) and finally 1/250 which is the full stop.
Aperture and shutter speed are inversely proportional. So if you increase your shutter speed by one stop you can decrease your aperture by one stop and get the same exposure. We’ll discuss more on this when we talk about Manual mode in a later post.
Below are some photos where you can see examples of how to leverage shutter speed to give your photos a different look. Off the top of my head it can be used to:
Show movement in a ferris wheel. This picture was taken in Sheffield a few years ago by me – I had the tripod setup and took an exposure for 20 seconds. The outlined highlight of the cars is due to the fact that the wheel paused for 5 seconds on it’s way down.
Capture a horse in motion. The picture above is a picture of a famous horserace in England, called the Royal Ascot. This requires a fast shutter speed to capture the galloping movement. This particular photo was taken at 1/320 of a second and created a fairly sharp picture but you can still see the movement in the horses’ hooves.
Back to “slow mo” you can take a longer shutter speed to create a sense of movement, even when it’s you that’s moving. The picture above was taken a few years ago on an escalator in the London Underground. This didn’t require an exceptionally long exposure to create the effect – this was taken for 1/6 second and the effect is subtle but gets the job done.
And finally my favorite. The above photo was taken in my home shower as part of my 365 project last year. I share this photo for two reasons. One is that I think it’s really cool.
The other more important reason is to illustrate something else about shutter speed – flash can sometimes “negate” the effect. This photo looks pretty crisp and clear, with the water frozen in time. However it was actually taken at 1/6 second. Since I used a flash though, the flash “freezes” the action when it goes off and can effectively create a stop motion effect, similar to if the photo had been taken at a much faster shutter speed. There are numerous advantages to using this technique but I’ll cover that in another post.
Finally, while we’re on the topic of water I’ll include the most obvious use of shutter speed and one that every photographer who’s got a DSLR will want to try out. And that’s taking a long exposure of water.
The photo above was taken in Iceland and was taken at 1/6 of a second. That’s not really a lot of time and yet the water has become a silky white. It really takes a tripod to achieve this and get a sharp photo. One great experiment you can do is to go out to a location that has moving water (the waves of the beach will do) and take pictures at various shutter speeds to see what results you get. Taking very long exposures can also create a beautiful glass effect on the water, as you can see here.
This wraps it up for my overview on Shutter Speed. I hope you find it useful and the above gives you some ideas on when you can leverage it to your advantage. My next tutorial post will be on ISO (far and away the easiest and most basic of the three factors that define exposure) and then we can get talking about Manual. Until then, enjoy capturing moments in time with an improved knowledge of your camera’s abilities.