Life is a series of moments that leaves us with memories, both splintered and whole.
If you are just joining us, the PRELUDE & SYLLABUS section is the logical starting point for the series.
Welcome to Digital Photography #101,
by Virtual Studio Photography (VSPHO)
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We left off in APERTURE Part 2 of 2 with a basic understanding of the APERTURE functionality.
Now that we have gotten through the toughest part, we are going to start having more fun!
In this section, we now progress to the next EXPOSURE variable as outlined in PRELUDE.
Understanding the concept of the SHUTTER SPEED is key to understanding the manipulation of LIGHT and MOTION.
We used the analogy in the previous Aperture section that the Aperture regulates the flow or quantity of light just as the faucet on the kitchen sink regulates the flow or quantity of water.
Using the same analogy, the SHUTTER SPEED controls HOW LONG the shutter is open just as the kitchen faucet controls how long you leave it open at any given water pressure.
The Shutter Speed is a function within the camera body. Since the early days of mechanical 35mm cameras, there became a standard set of Shutter Speeds most cameras had in common.
They were basically: B (bulb) keeps the shutter open, 1 full second, 1/2 of a second, 1/4 of a second, 1/8, 1/15, 1/30, 1/60, 1/125, 1/250, 1/500, and maybe 1/1000. Of course, 35mm cameras progressed well past these speeds in each direction, but the shutter speed was still mechanically controlled.
With computer controlled digital cameras, the shutter speed range has vastly expanded in both directions, including the established speeds PLUS speeds of 1/2 and 1/3 increments in-between the standard speeds. It is common for top DSLR cameras to offer Shutter Speeds as long as 30 full seconds (requiring a tri-pod, discussed in a future section) to 1/8000 of a second. (Of course Bulb is still included.)
Along with controlling the quantity of light that is allowed to enter for the EXPOSURE, the SHUTTER SPEED also allows you to control MOTION in your pictures. As previously outlined, the Aperture allows for artistic creativity through the Depth of Field, the Shutter Speed equally encourages artistic creativity through MOTION. (We will discuss further down.)
For the beginning photographer, controlling the Motion of Moving Objects is just as important to master as the Depth of Field is for the Aperture.
So let’s start off with keeping our pictures sharp and free of any unwanted blurring due to motion.
The standard Shutter Speed setting for our standard 50mm Focal Length lens is 1/60th of a second. This is called the Reciprocal of the Focal Length. Stated perfectly, it would be 50mm Focal Length with a 1/50 of a second Shutter Speed, or a 250mm Focal Length with a 1/250 Shutter Speed and so on…
This allows in the most light possible without causing blurring due to “some” movement of our subject. Likewise, this speed (1/60 of a second, 50mm lens) compensates for slight motion caused by our own shaky hand. (Within reason.)
So here is the simple rule of thumb to maintain the same ratio of Shutter Speed (Reciprocal) at any given Focal-Length:
Whenever you double your Focal-Length, you double your Shutter Speed. With fixed Focal-Length lenses or variable zoom lenses, this rule stays constant.
Example: We started with the standard of 1/60 for a 50mm lens. If we ZOOM to a Focal-Length, say between 70mm and 125mm (a slight telephoto lens), we change the Shutter Speed to 1/125 of a second. If our Digital Camera has incremental Shutter Speeds, we can match the Reciprocal perfectly (e.g. 70mm Lens with a 1/70 Shutter Speed).
Likewise, if we ZOOM to a Focal-Length, between 130mm to 250mm Telephoto lens, we change the Shutter Speed to 1/250 of a second.
This “only” keeps the Ratio of Shutter Speed to Focal Length the same. This is also easy to remember as the Shutter Speed matches the Focal Length (250mm lens = 1/250 Sutter Speed; 500mm lens = 1/500 Shutter Speed…)
Likewise, keeping the Shutter Speed FASTER than the Focal Length keeps even faster moving objects frozen. e.g. 125mm lens with a 1/250 Shutter Speed will stop the motion of a person running (Twice the speed of the Reciprocal). With our same 125mm lens Focal Length, a Shutter Speed of 1/500 (4 times the speed of the Reciprocal) would make the propellers of a helicopter in flight look frozen like a toy on a string. (Note: The distance of the subject plays a part, I will touch on Motion Parallax Phenomenon in the examples below.)
The drawback is that every time you DOUBLE the Shutter Speed, you DECREASE the light by 1/2. (Common sense.)
Conversely, DECREASING the Shutter Speed each increment DOUBLES the amount of light. (1/125 allows TWICE the light of 1/250)
So let’s move into an intermediate level of Shutter Speed MOTION manipulation.
This first picture represents combining the Shutter Speed of Stopping Motion with a small amount of Blur for Motion Affect. Our mini-model is still crisp with no Blur, while the stick she is about to heave gives us a visual sense of Motion.
Hold the CNTL key and hit + or – to control the image size.
Click HERE for PICTURE. Then hit the “back arrow” at top left of page to return. If the picture comes up BLACK, just hit the screen REFRESH key, Round Arrow upper left of screen.
Our mini-model was shot with a focal length of 75mm with a Shutter Speed of 1/90 of a second. The same 1/90 Shutter Speed would have frozen all motion with a Focal Length of 50mm.
Likewise, this jump-rope athlete was shot with a wide-angle of 27mm (covered in the upcoming lenses section) with a Shutter Speed of 1/80 of a second. A very fast Shutter Speed for a 27mm Focal Length (close to 3X the Reciprocal), so he is crisp and sharp but the rope is moving considerably faster than the stick of our previous mini-model.
Hold the CNTL key and hit + or – to control the image size.
Click HERE for PICTURE. Then hit the “back arrow” at top left of page to return. If the picture comes up BLACK, just hit the screen REFRESH key, Round Arrow upper left of screen.
Stopping any motion can easily be accomplished by increasing the Shutter Speed. Most DSLR cameras are capable of Shutter Speeds of up to 1/8000th of a second. Short of a speeding bullet, this shutter speed (1/8000) will stop motion even on high power telephoto lenses. (We will cover more on telephoto lenses in an upcoming section on Lenses.)
As motion (blurring) is a cool effect, you usually still want the actual subject to be sharp. To accomplish this with rapid moving objects (e.g. race cars in motion), you would use a technique called “Panning.”
Panning is a talent that you master with experience. Panning can be used on any moving target. It adds a sense of motion to runners, race cars, speed boats…
But first, if you were photographing a race-car on the track, you could totally stop the motion with a very Fast Shutter Speed in relation to the Focal Length. Depending on the distance of the speeding cars, we may be able to stop motion with just one or two Shutter Speed increases. Of course, one increase doubles the speed, and reduces the light by 1/2. A two Shutter Speed increase quadruples the speed, and decreases the light to 1/4th of the original shutter speed.
So there is a Double bonus to panning. Along with maintaining the light at the current f-stop setting, you are adding the sense of motion to the background (Blurring the background with a STREAK of motion, not just Out of Focus as with the Aperture).
To accomplish this, you can practice this by following a moving target (panning) and pulling the trigger when your target is in position.
The actual Shutter Speed you use is your choice as to how much blur you want for the background and how good you get at panning.
As we know, the Aperture regulates the amount of light, but affects the Depth of Field. But having a short Depth of Field will probably not harm the picture or the subject in our picture as they will still be in focus.
But, a Shutter Speed that is TOO SLOW for the given Focal Length can mess up every picture with just simple hand movement.
In our last example, we have an obstacle course:
“The Tire Flip.” Once is not bad, but flipping this 200 pound tire several times is a workout! *laugh* It’s fun to watch, so:
This was shot with a 27mm Focal Length and a 1/15 of a second Shutter Speed.
In this first shot, please note the traffic in the background. This is the perfect example of Motion Parallax Phenomenon. That means that proportionally, the further away an object is, the slower it is moving from your perspective. Simply notice that the cars in the center are blurred somewhat, but the cars to the far left in the distance are almost sharp. (More on this in a future section.)
Hold the CNTL key and hit + or – to control the image size.
Click HERE for PICTURE. Then hit the “back arrow” at top left of page to return. If the picture comes up BLACK, just hit the screen REFRESH key, Round Arrow upper left of screen. In this next one, Motion Blur is disproportional (but funny to see). This example of Motion Parallax Phenomenon is the effect of being close to the subject with a Slow Shutter Speed. As our subject rapidly moves through the Field of View, the amount of light needed to produce a sharp image is scattered along the moving path.
Hold the CNTL key and hit + or – to control the image size.
Click HERE for PICTURE. Then hit the “back arrow” at top left of page to return. If the picture comes up BLACK, just hit the screen REFRESH key, Round Arrow upper left of screen.
In this third picture, the loss of image segments is the extreme effect of Motion Parallax Phenomenon. Some of the image actually looks transparent.
The effect is surrealistic!
Hold the CNTL key and hit + or – to control the image size.
Click HERE for PICTURE. Then hit the “back arrow” at top left of page to return. If the picture comes up BLACK, just hit the screen REFRESH key, Round Arrow upper left of screen.
We will get into using a tripod and longer Exposure times (longer Shutter Speeds) in the EXPOSURE section, but nothing will mess things up faster than Too Slow of a Shutter Speed!
I just created an new section to preceed the ISO Sensitivity.
35mm FILM versus DIGITAL IMAGING will add much needed insight to the next section, ISO Sensitivity.
Virtual Studio Photography (VSPHO)