Episode 4;      Shutter Speed and It’s Importance

 

A camera’s shutter speed controls the duration of the amount of light that hits the sensor.  Done creatively, it can help to convey action by blurring the image or by freezing it. When the camera’s shutter is open, it allows light to enter through the lens and then onto the sensor plane.  In older film cameras  a black curtain of material or thin metal opened and closed to allow light in. Now with digital cameras light is let in via the lens opening and closing a set of very thin interlocking blades called, “leafs.”  The term “shutter speed” represents and average amount of time hitting the sensor over a timeframe.

Basically, if the image contains moving objects or subjects, you have to decide whether or not you want them to be crystal clear or to be blurred.   The control of the shutter speed is not done in isolation without affecting the exposure or image quality. Shutter speed is measured in seconds or in fractions of a second.   The larger the number, say 1000 the faster the speed.  Numbers below 100 are considered to be slow shutter speeds.  My rule of thumb here for normal hand held shooting is too keep the shutter speed above 1/100^th of a second. If you can shoot with a slower speed, say 30^th of a second and still have a clear(non-blurry) image, my hat’s off to you. Anything below 100 is hard to hand hold because of shaking the camera when you depress the shutter button.  This is precisely why I always use a tripod to do hotel work because I am always using long exposures, sometimes as long a 1-2 minutes.

 

                                                                            

Shutter speed dial.

 

                                                                 

Here is a shot that I tried to capture with the camera on a tripod and the shutter speed at 1/60^th with the lens at f2.8.  Unfortunately the model moved .  We had to either increase the shutter speed, increase the amount of light, or make sure the model did not move.  We asked her to hold still and the shot worked great.

Shutter speeds on your camera, in manual mode of course, are approximately doubled with each setting. 1/30^th,  1/60^th,  1/120^th, etc.  Every time you move the dial you are increasing or reducing the light coming in by one stop.  Your camera may have what’s called  “bulb” mode, which means that you can keep the shutter open for longer periods of time.

Another rule of thumb; to freeze action, you use faster shutter speeds( 1/125^th to 1/500^th, and beyond) and to blur a shot, you would use slower shutter speeds(1/30^th, 1/15^th, 1/8^th, and lower.)

 

                                               

In this room shot,  I forgot that the air conditioning was on and the movement of air actually moved the window shears enough for them to blur out. I was shooting at f14 at a shutter speed of 1 second.  I turned the air conditioning off.

When shooting interior such as this, you really have to concern yourself with shutter speed and things moving around in the shot.  Usually, interior shots are done using long shutter speeds, and therefore anything like window sheers, curtains, flowers,  leaves on small trees, etc., can become a problem if not considered ahead of time.

The technical stuff now.  Remember that shutter speed control does not work in isolation.  If you adjust the speed from 1/60^th to 1/125^th you will be cutting the amount of light hitting the sensor by 1 stop, which means to get the same exposure that you wanted, you will have to open the lens aperture by one stop and visa-versa.  It’s all just math.

 

                                                                   

Here is another example where the wind can play havoc with your images. Great shutter speed for the building, but not for the flag.  The solution?  I had to reshoot the flag at faster shutter speed, and strip in in with photoshop.   There is always a solution.