Shutter Speed, ISO, and Aperture


Exposure refers to the amount of light that enters the camera and hits its digital sensor.It is basically the measure of how dark or bright a photograph is.

If the image is too bright, it is then said to be overexposed.This is whereby too much light has been allowed to hit the camera’s sensor.If it’s too dark, it is said to be underexposed and not enough light has been allowed to hit its sensor.


                                 {above is an example of an underexposed image}

overexposed                             {above is an example of an overexposed photograph.}


The aperture refers to the size of the opening in the lens through which the light enters the camera. The size of this opening can be adjusted and the aperture size is measured in f-stops. The image on the right shows you exactly what the aperture on a lens looks like.

When you change the f-stop value, you change the size of the opening. Here’s the weird thing though. The higher the f-stop, the smaller the opening.

Take a look at the chart below to see what different apertures look like at different f-stops. On the far left, you can see that setting an aperture of f16 will result in a small opening. Choosing an aperture of f1.4 will result in a very wide opening.


The choice of aperture affects your photograph, but the most noticeable affect your choice of aperture and on the depth of field.


The shutter speed refers to the length of time the opening in the lens remains open to let light into the camera and onto the sensor. The shutter speed can be as fast as 1/10,000 of a second or as slow as several minutes.Fast shutter speeds have the effect of freezing motion in the scene you are photographing. Conversely, slow shutter speeds will blur motion in a scene. Both of these can be used to great creative effect.

The chart below shows how different shutter speeds would effect the sense of motion if you were photographing a person running. Fast shutter speeds will freeze the motion. This technique is often used in sports photography. The slower the shutter speed becomes, the more blurred the person running becomes in the photograph.



The ISO refers to how sensitive the digital sensor in your camera is to light. The lower the ISO number, the less sensitive it is to light. Setting a higher ISO number increases the sensitivity of your camera sensor to light. Most cameras have ISOs ranging from about 50 or 100 ISO right up to 16,000 ISO or higher.

As you increase the ISO value, your camera sensor becomes more sensitive to light. This means that you can achieve higher shutter speeds. This can be extremely useful when shooting in low light without a tripod. You may find that shooting at 100 ISO results in shutter speeds that are too slow to hand hold without camera shake. By increasing the ISO to 800 ISO for example, you may find that your shutter speed is now fast enough to hand hold.

 compiled by Barry o. Carroll



When one is presented with different potential scenes, it’s necessary that he/she knows how to set up their camera in order to make the1-1246451608rmul most of what’s in front.











Digital SLRs cameras have a choice of exposure modes which offer varying levels of controls.Scenes modes are best avoided for landscape photography and only in the program mode where you simply can’t predict the effect you wish to achieve with the degree of consistency.One requires full control over aperture selection, as it dictates the level of depth of field.Either way one can use the manual mode which is also useful but it relies heavily on your input.



This is used to alter the exposure from the value selected by the camera, making photographs brighter or darker.In mode P, S, and A, the camera automatically adjusts settings for optimal exposure, but this may not always produce the exposure the photographer intended. Exposure is a matter of personal preference, and an exposure brighter or darker than that selected by the camera may sometimes better reflect the photographer’s intent. The feature used in such situations is called exposure compensation. DSLR Cameras allow you to check the results immediately, so you can take a photograph, display it on the monitor, and then raise exposure compensation for brighter results or lower exposure compensation for darker results and take another picture.

                                                                                                                    by NikonMeteringModes.jpg.


Cameras have choices of metering patterns which is typically multi-zone, center-weighted and spot.Spot metering is useful if you need to be very precise with your meter reading or maybe in order to calculate the contrast in light between the land and sky.

Metering is also used to measure the brightness of the subject. The camera optimizes exposure by adjusting shutter speed, aperture (f-number), and ISO sensitivity according to the brightness of the subject, which is measured using the camera’s built-in metering sensor. The camera does not simply measure the overall brightness of the frame but measures brightness separately in multiple areas of the frame. The metering mode determines which areas of the frame are used by the camera to measure subject brightness and how the camera sets exposure.

Normally the camera uses matrix metering, in which it divides a wide area of the frame into multiple segments and sets exposure based on a variety of information, including subject brightness and color. You can also choose center-weighted metering (in which the camera assigns the greatest weight to the center of the frame) and spot metering (in which the camera meters the area around the selected focus point).Choosing a metering method according to the scene and your creative intent allows you to achieve results that better mirror your artistic vision.

                                                                                                                          by Nikon