The second part of the Triangle Exposure

Last entry was focused on ISO, what it meant and what considerations you should take. This time, I am going to explain about Shutter Speeds or in other words how much time we will expose the film.

In the history of photography Shutter Speed became after the aperture, but I think is easier to understand. Before standardized shutter speeds,  the photographer just put off a lens cap and wait a little time to just cover it again, something that today stenopeic photographers still do. As manufacturing technics advanced, and different ISO sensibilities became much wider, different shutter speeds appeared. Like many concepts in photography, shutter speed was determined by dobles and halfs. So if we take for instance, one thousand of a second the starting point, the double of light we need is: (1/1000)/2 (one thousand of a second divided by two) will equals 1/500. And so on.

1/1000

1/500

1/250

1/125

As long for this seems very straight forward, due the fact that 125/2 will equals 62.5, makes very specific to do mechanisms, they went to the easiest nearest value 1/60.

If you make the division:

1/62.5 = 0.016

1/60 = 0.01666667

so, its the same…

1/60

1/30

1/15

1/8

1/4

1/2

1"

Most old cameras will have a dial with this values, but those, will be without the "1/" and only show the denominator of the division, so you will see 1000, 250, 30, etc.  In later models, the ones with digital displays, will have medium values, for example: one between 1/60 and 1/30, 1/45. These are called half stops, and digital cameras will have thirds of a stop. Also this electronic cameras will have longer times programed, from 1 second (1") all the way to 30". Some old cameras will have different colored numbers. The most commons are:

• 60 Synchronization speed
• 30 or under, shutter speeds too low that are not recommended to shot the camera unless you use a tripod or other stable elements (like a table).
• In some cases only 1 comes in a different color, representing is 1 second

Most SLR, because not all (like the Canon T50) will have a B on the dial. This B means Bulb, this mode or selectable speed is a speed chosen by the photographer, more like the old days, and is used for longer exposures, longer that the slowest time that the camera let. The shutter will be open as long as the shutter button is pressed. But as mentioned with speeds slower than 30, you are going to need extra help, from a tripod, or something else that could keep the camera fixed. In the case of the B, is also recommended the use of a shutter release cord. Older cameras will have more standardized accessories, while electronic ones, in most of the cases, will only accept first party cords. The cord will have a block system, in which there is no need to be continuously pressing the shutter, just to remember when to release it.

As for some mechanical cameras, and all semi-automatic, you could choose freely the speed. In old cameras, some lenses had an A, mostly in green, in the aperture selection ring, and in the electronic cameras, there is a mode called Tv (Canon and Minolta) or just S in Nikon. So by now you are not going to worry about selecting the right aperture value. The next week topic.

There are two major effects created by the shutter speed, blur or still.

Blur

It is said, and it is true, that the whole Universe is in motion, but depending on which point of view we have chosen, things may be moving or may be still. Most of the times people think photography is just a moment captured, although, a photo is able to record the succession of moments in just one shot, it can illustrate trajectories.  This effect is going to give a sense of motion, and it is not very hard to achieve.

The only consideration we have to think about is the velocity of the object we try to photograph. For example: we see a juggler and he is doing some fancy stuff with his toys, we could try to have a sharp still image of his face but not of his toys. In this case his toys are moving way more faster than the juggler, he is standing still and just his hands are moving. The slowest speed in which I am able to shot without a tripod, is 1/30. So if he is standing still, and just moving his hands, the end result may be of some blur on his hands and his toys, while his face may seem still. If I would go with slower speeds, if I had the tripod, I could be in risk of making everything blurry, even the juggler. 

But in shiny conditions, if you are able to do it with sunlight, very long exposures will tend to "erase" the blur, as the original object you tried to blur is no longer in front of the camera, and the objects behind it will start to show in the image. The only sure blur that will last long enough, are when at night, you do it with objects that emit light, like cars or county fair rides, they last because the background is dark, and it takes more time to be exposed.

Still

For many years of advertisements, the still has been the selling point for cameras, even nowadays, in which there are cell phones with very sensitive sensors… Just as in school, the opposite of blur is the still, in which everything that may be in motion will appear frozen in time, that magic moment in which many sport photographers rely on.

Remembering the Juggler and his toys, in this case we want to have everything still, so we are going to go the opposite way in the shutter speed scale, as his toys may be moving in quite a fashionable way, we will try to set it to 1/250, the blink of the shutter may be fast enough to just see the toys just that 0.004 of a second, not letting expose the trajectory.

The next two images are little examples of a blur and a still, it was made with a digital camera, just for didactic proposes.

This image was shot 1/45, you can clearly see how pages overlap above them.

This one was shot with 1/125, maybe it does not see very obvious, but all the pages look like if the were still.

I leave you with the video tutorial in which I show you how shutter speed is controlled by the camera, and how to select it on a semi-automatic camera.