Understanding Shutter Speed

I think it’s best if we start off with a quick explanation of what the camera shutter is before we get into the fun part of messing around with it.

The shutter is simply a door that opens and closes letting light pass through to the sensor/film. Whew! Glad we got that out of the way. In all seriousness that is all you really need to know about what a shutter is. What really matters to you and this blog post is the amount of time that shutter door stays open (better known as your shutter speed).

This post’s goal is to get the technical things out of the way. Once you understand how shutter speed works, than we can go on and talk more about what you can do with it.

Shutter Speed and Exposure

Now I’ve talked about this before in a post about the photographic triangle, so I won’t go into details here. But since you’re here and not there, here’s an over view.

Exposure = Shutter Speed + Aperture + ISO

All three of these affect your exposure and control the amount of light hitting the sensor. Too much light and you’re overexposed, not enough and you’re underexposed. Your ISO represents how sensitive the sensor is and the aperture controls your depth-of-field (what’s in focus and what’s not). The aperture is the diaphragm in front of the shutter that controls HOW MUCH light comes in.

The shutter speed affects HOW LONG that light is allowed to hit the sensor. Your Shutter Speed and Aperture usually work hand-in-hand, so if you already have the correct exposure but decide to change one you’ll have to also change the other. In this post we’re not really going to talk about the aperture, so let’s assume that if we change the shutter speed that the aperture was also changed to make sure our exposure is right. This way we can talk about the affects changing the shutter will have on your photo.

Shutter Speed – Basics

So you see shutter speed numbers like 60, 125, or 250, but what do those numbers mean? Well, they’re actually fractions of time. The number 60 actually means 1/60th of a second (125 is 1/125th, 250 is 1/250th, etc). Over time, shutter speeds have been standardized so these numbers should be familiar to you.

Sometimes they’re not fractions of a second. Sometimes they are full seconds. Higher end camera can have a shutter speed range of 30 seconds down to 1/8000th of a second.

Have you ever noticed a “B” setting on your camera? Wonder what it is for? The “B” stands for BULB. No, not flash bulb. Back in the day photographers used to squeeze a bulb that would open the shutter and it would stay open till you let go. You can do the same now with cameras when you use the Bulb (B) Mode. The shutter will stay open till you release the shutter button. Of course, you would generally use this when you need a long, or very long, exposure so you really don’t want to be touching the camera and shaking it. If you’re going to use this feature get are shutter release trigger, or a wireless shutter release trigger. That way you’re not moving the camera while it’s taking an exposure.

Changing STOPS of Light

Just as you can STOP UP (doubling the light) or STOP DOWN (halving the light) with your aperture, you can do the same with your shutter speed. When cameras were first invented the photographer would just remove the lens cap to let light in and place the cap back on after enough time passed to create the exposure. As film became more sensitive a faster shutter mechanism was needed.

By this time apertures were represented with a standardized system of doubling/halving the amount of light that passed through the diaphragm, so a similar 2:1 scale was adopted for shutter speeds. Check out my post about f/stops and Apertures if you want to know more. Below is the standardized shutter scale:

These aren’t the only shutter speeds available and just like with apertures, you can adjust your shutter speed by a third of a stop. So if you are using 1/60 and don’t want to STOP DOWN one complete stop to 1/125, than you can move it down a third of a stop to 1/80th a second, and down again to 1/100th a second. This gives you a bit more control over your exposure.

Here’s a quick note: In your camera you may see 1/60 represented as 60 and 1/125 as 125. Don’t be confused by this. You may be thinking that if you’re at 60 and you want to STOP DOWN, then you should go to 30 rather than 125, since 30 is smaller and 125 is larger, but don’t forget these are fractions. 1/125th a second is shorter than 1/60th a second, so the light has half the amount of time to hit the sensor.

Shutter Priority Mode (Tv Mode)

There are two situations in which you should make the shutter speed your first priority: when the scene offers motion or action opportunities, or when you find yourself shooting in low light.

Shutter Priority Mode (also referred to as Tv Mode or Time Value Mode) is a semi-manual mode. With Manual Mode you control it all, but with Shutter Priority you set the shutter speed and the camera will worry about the aperture. This is good when you know you want to use specific shutter speed but you know the exposure will be changing.

If your subject doesn’t move, and your camera isn’t moving, you could easily do full manual mode, but maybe you’re trying to shoot racecars or a child running around. With photos like these, you are more interested in capturing a sharp image and less interested in the depth-of-field. Btw, your SLR also has an Aperture Priority Mode too which does the opposite, but we’re not covering that in this post.

Example of what we’re talking about

Say you’re taking a picture of your child running in the park. To freeze the action you set your cameras shutter speed to 1/500. But your child is running in and out of the shade and the scene (and exposure) keeps changing from bright to dark. If you are set to shutter priority than the shutter will stay at 1/500 and the aperture may change from f/11 in the sun and f/5.6 in the shade.

Since you are only worried about having the correct shutter speed, you are free to take many photos while the camera worries about the exposure.

Hand Holding and Camera Shake

Ever wonder why your photo is blurry? You know, you’re at a bar, or in someone’s house, at a concert, or a church wedding and you tell people to say cheese, but they just keep coming out blurry. Well, it’s cause you’re shaking the camera. I know, you were holding it still, you swear! But the truth is no matter how you hold it, it’s going to shake. Just pressing the shutter button down shakes the camera.

The problem is that your shutter speed is too slow, so even the slightest movement blurs your photos. As a general guideline when hand holding your camera you should shoot at 1/60 or faster. In most cases 1/60 will be fast enough that camera shake isn’t noticeable.

Now, that’s just a guideline, but there are exceptions. Sometimes you can hand hold your camera and shoot with a slower speed of 1/30 or maybe 1/15. Three things can help you out.

• Try to bracing the camera. Use a railing, a door, table, car, anything sturdy. If you don’t have anything nearby use your leg, or brace your hands on your face. And make sure you tuck in those elbows to your body. That will make you a more stable shooter.
• Get equipment with with Image Stabilization features. This will help compensate your hands shaking and may buy you an extra couple stops of light.
• Set your camera in continuous shooting or burst mode. This way you take 4 or more photos one after another. One of them is bound to come out sharp… right? Well, if you have no other choice it’s worth a shot. There’s actually a fourth way too, but I’ll mention it in the next paragragh.

Ah, but the rule changes again. It all depends on the focal length of your lens. As a guideline your minimum shutter speed should match your focal length. 1/60 is good if you’re using a standard lens, but if you’re using a 200mm or 300mm telephoto lens, then your shutter speed should be at least 1/200 or 1/300 respectively. Of course this works the opposite way as well. If you’re using a wide angles lens at 24mm, you have a better chance of using a shutter speed of 1/30 and getting away with it. The reason for this is because of the field of view the lenses have. Telephoto lenses get up tight, so even the slightest movement will be picked up if your shutter speed is too low. Wide angles tend to be very forgiving.

One last point… it matters how close you are to your subject. If the subject is far away or small in your frame, you can get away with a slower shutter speed. If your subject is close, or large in your frame (cause you zoomed in close) then you need to use a faster shutter to avoid blurring.

Don’t let this confuse you. Here’s what’s important. A sunny day with a standard lens, use 1/60 or faster. If you use a telephoto lens (ex: 200mm) than your minimum speed should be 1/200. 300mm minimum is 1/300. Got it.

If your find you need to use a faster shutter speed to get rid of blurring, and your aperture is at its widest opening, then increase your ISO. This will make your sensor more sensitive to light and you can decrease the amount of time your shutter stays open.

Conclusion

OK, so now that we got all the basic shutter information out of the way we can move onto the creative side of shutter speed. But before we do, let’s run down some of the main points you should take away from this post.

• Shutter Speed is measured in seconds
• You’ll probably be using 1/60 or faster in most situations
• Anything slower than 1/60 will likely need a tripod
• The standardized shutter speed scale doubles/halves the amount of light hitting the sensor.
• Consider your focal length when choosing your shutter speed.
• Depending on your shutter speed, you can freeze or blur your image, but more about that in the next blog post: Creative Shutter Speed and Showing Motion