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All posts for the month March, 2010


I’d like to continue our series of discussions on exposure-modes. Yes, I know with the last installment over 6 months ago, it can’t really be called a continuation. Perhaps an extension, extended-leave, or vacation, whatever you’d like to call it we’re going to chat about our next semi-manual exposure mode, Shutter Priority Mode (S).

Shutter Priority Mode or S-Mode functions very similarly to Aperture Priority Mode or A-Mode, it just does it from another point of view. Shutter Priority Mode allows you to manually set the shutter speed of the camera, or how long the shutter will remain open when you take a photo. In Shutter Priority Mode the camera will automatically set the aperture for you based upon the shutter speed that you choose.

Shutter speed is measured in time (seconds). Usually very small parts of a second such as 1/500th of a second, or 1/1000th of a second for shooting in very bright conditions, such as high noon on a bright sunny day. Or in full seconds such as 1 second or 30 seconds for shooting in low-light conditions, such as indoors by candle-light.

The shorter the shutter remains open for, the faster the shutter speed. For example, a shutter speed of 1/250 means that I could take roughly 4 photos in the same amount of time than if I was using a shutter speed of 1 second. This is because at a shutter speed of 1/250 the shutter is open nearly 4 times shorter than if I was using a shutter speed of 1 second; hence we say that 1/250 is a faster shutter speed than 1s.

By using a faster shutter speed, the cameras shutter will be open for a shorter amount of time, which means less light will be allowed to hit your digital sensor, or film. This is why we use faster shutter speeds when we are shooting in bright conditions. When we use a slow shutter speed, the shutter remains open longer and therefore lets more light into the camera to hit your digital sensor or film.

Now I know what you must be thinking at this point…”Scott this is all very fine and good information, but if I wanted to change the amount of light that enters my camera I could’ve just used the Aperture Mode that I learned about 6 months ago and not have wasted my time with the last 4 paragraphs.”

It is true that aperture also controls the amount of light entering your camera by varying the size of the shutter, and you will recall from our earlier discussions that aperture size and shutter speed are linked together. So why would you want to change the shutter speed instead of the aperture?

Well just like varying your aperture controls your depth-of-field, shutter speed has a side-effect as well. Changing your shutter speed allows you to “freeze” the action in your photos. The faster the shutter speed the more “frozen” your subject will be.

Imagine if  you were trying to photograph your child in his or her first little league game. They are about to make the winning slide into home plate. By using a very fast shutter speed we would be able toshow the exact instant their body touches the plate, and it would be extremely sharp and in focus.

Some digital cameras that do not have a Shutter Priority Mode may have a “sports setting”. Using the “sports setting” will force your camera to take photos using a fast shutter speed, usually 1/500 of a second or greater. Just keep in mind that you’ll need bright sunlight in order to shoot at such a fast shutter speed.

Take a look at this photo of a car doing aerial stunts, caught in mid-jump. Shooting with a very fast shutter speed, 1/800 in this case allowed me to “freeze” the action of the car while making sure it retained sharp detail. Also notice that the photo was taken in very bright sunlight as anything less than that would have yielded a photo with blur.

Jumping Car

“Frozen” Jumping Car, 1/800

So now that we know some exciting things that we can do with fast shutter speeds, when are some appropriate times to use slow shutter speeds? Slow shutter speeds allow you to create some very beautiful artistic effects in your photographs.

Imagine a beautiful waterfall cascading into a pool of water. If we used a fast shutter speed to shoot the waterfall we would end up with a very boring photo of sharp, “frozen” water. All of the beauty of that waterfall rushing over the mountain would be lost. There would be no sense of motion.

We can correct this by using a slow shutter speed. If we shoot the waterfall using a shutter speed of say 2 seconds, we will retain all of the motion and power that waterfall has, and end up with a beautiful photo of a nice silky waterfall. Just resist the urge to dive in, remember your camera doesn’t like water. :)

In the photo of a carousel race horse below, we are able to convey a sense of the motion of the carousel to the viewer by using a slow shutter speed. Although the main horse is relatively sharp and in focus, if you look to the other race horses moving around in the background you’ll notice they all have motion blurs, thanks to the slow shutter speed that was chosen. The slow shutter speed helps to instantly evoke thoughts of a moving carousel to anyone looking at the photo.

 

Derby Horse with Blur 1/30

Derby Horse with Blur 1/30

Slower shutter speeds are also used in low-light situations. It is important to remember that our cameras have a very different definition of low-light than we do. Think about it, how many times have you been in what you would consider a perfectly bright house, but when you try to take a photo, your camera almost always wants to pop up that flash! This is because our eyes are much more sensitive to light than even the most high-end camera.

Have you ever tried taking that same photo without the flash? It usually winds up dark and blurry. This is because your camera naturally chooses a slow shutter speed. With such a slow shutter speed your subjects will not be “frozen” so even the slightest movement of either them or you causes blur.

This is why god invented tripods. It was dark in those tents in biblical times, how else were the photos going to be sharp :)

For those of us with cameras that don’t have an S-Mode, your camera might have a “night mode”. When you place your camera in “night mode” it forces the camera to shoot at a slow shutter speed, usually 1/30 or slower. How many times have you heard someone complain “my camera is broken, every time I shoot in night mode my photos come out blurry”! Now you know why. You weren’t one of those people were you? :)

Now that you have a new creative tool in your photography belt, I implore you to go out and give it a try! Next time we’ll combine the best of Aperture Priority Mode and the best of Shutter Priority Mode into one big manual mode that we call…well we just call it Manual Mode :)