Most people do not quite understand how their digital camera works and their pictures suffer for it as a result. One of the important things to understand is the “ISO” number or the shutter speed. By manipulating how fast the shutter blinks a number of different details enable a photographer to obtain different effects.
Combined with the camera’s f-stop, this makes it one of the most important numbers on your digital camera, making it worth keeping track of in terms of how it affects your pictures.
What ISO Is All About?
An interesting question is why not all cameras use the same ISO, say of “50”, but access a range of numbers. To understand that we need, the ISO number, from a transliteration “International Organization of Standards”, measures how much light is captured, with greater numbers equating to greater sensitivity.
When film was used as the medium for photography, grains of silver were used instead of shutter speed; while the smaller the grains, the more sensitive the film.
The number under 1 refers to the size of the grains in an inch (this is why 200 is actually larger than 800 in this case, as “200” means “1/200” and “800” is “1/800”). However, as digital photography does not use film there are no grains, but use shutter speed instead to simulate the same effect.
In digital photography, the grains have been sort of replaced by pixels or at least groups of them. The longer that the shutter is opened, the smaller these groups of pixels are, while the shorter that opening the larger these groups of pixels.
Camera Resolution
This is a resolution matter more than it is anything else, as the groups become smaller with more current models. However, it is an issue that only those truly interested in digital photography need to be worried about as most people would hardly notice and it is virtually removed when the photograph is translated to lower resolutions for other purposes.
This, by the way, is what people refer to as “noise”; the lower the ISO the less the noise.
In a digital camera, the numbers start at “200”, it means that the camera’ shutter is opened for 1/30 seconds, depending on the camera setting, as some are faster others slower. Doubling the number halves the amount of time that the shutter is opened, so 400 and 800 translate to 1/60th and 1/120th, respectively.
There is a trade-off when it comes to shutter speed: The longer that the shutter is open, the more detail is possible, but a shorter speed allows for the ability to stop time. A digital camera must, therefore, balance the two in order to create the best possible picture for the circumstances.
Issues That May Arise With Lighting
There are two problems here. The first is that the less light in the area, the more time the shutter needs to be opened; torchlight requires a much lower ISO than a bright day, for example.
At the same time, the longer that the shutter is open, the more likely that there will be “shutter shake”, and the more likely that the picture will be blurry; the body is moving all the time and holding the shutter open makes this more apparent.
This also means that an ISO of 50 would hardly be practical for almost any kind of digital photography; it would cause washed out pictures in normal conditions, as too much light is let in, and there would be a lot of shutter shake. But there is much more that needs to be discussed.
Shutter Speed And Effects
Shutter speed allows for a wide range of dramatic effects. A longer shutter speed allows for more detail in the photograph, while shorter speeds can effectively slow down downtime.
The former translates to brighter, crisper details in the picture making for greater and deeper detail, but most photographers are advised to use a tripod at lower speeds in order to defeat shutter shake issues.
Of course, this makes extremely long shutter speeds, such as leaving the shutter open for minutes or hours at a time, all the more interesting as a tripod must be used in order to get clear shots.
Conversely, the latter means that the target can be effectively slowed down, cutting out the blurriness of speed and allowing for sharper details at higher speeds. Of course, there are limits to how sharp those pictures can get, of course, and at some point, the limits of the digital camera will become apparent.
In essence, no matter how good the camera is, the shorter the shutter is opened, the more noise will enter the picture.
Also, the faster a camera is, the more likely other details will be missed due to timing and aiming; this is why a tripod is used for aiming and keeping the camera focused where it needs to be focused just as multiple shots are used to ensure that the precise moment is captured.
F-Stop And Light Sensitivity
It is also important to consider the effect of the f-stop on pictures as well, but only as much as it is also the balance to the shutter speed.
In this case, the f-stop can be used to help increase light sensitivity as well, helping the digital camera deal with the lack of light. If the light is exceedingly low, the aperture of the camera should be opened as much as possible in order to let as much light in.
The Bottom Line
All of this means that there is a good reason that the digital cameras are not all ISO 50. While it would allow for some really nice detail when it comes to pictures, the would be the problem that there would be some shutter shake from the person holding it.
Everything would also seem to be a little blurry as well from the time that the shutter was opened. Lastly, the shots would be great for night and some party shots, but pictures taken in daylight or even if properly lit would be washed out.
All of this means to make sure that you check the ISO of your digital camera before shooting for the best possible pictures.
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