no consumer

If you set the aperture too small for the conditions that you are shooting in, your photograph will appear too dark (under exposure),and if the aperture is too large, your photograph will appear too bright (over exposure).

Most cameras, particularly SLRs, allow you to set the exposure, and will measure the light available and advise you if the exposure is too great or too little.

Aperture can be used in combination with shutter speed to maintain a constant amount of light entering. If you are using a large aperture (low f-stop numbers) you can decrease the shutter speed to allow the same amount of light onto the sensor. This type of setting will increase your depth of field – more of your image will be in focus. If you are using a small aperture, you can increase the shutter speed, which will decrease your depth of field, allowing you create the effect where only a small portion of your image is in focus, and the rest of image maintains an attractive blur.

Chart showing the openings and measurements

Aperture Pdf [PDF, 49 KB]

Sometimes you may face a situation where the automatic exposure (AE) on your camera cannot determine what the subject of your photograph is. If one area of the image is in shadow while another is brightly lit, the camera will expose for an average of the area, and all of the image will be poorly exposed. This is when you will need to use exposure compensation. If the focus of your image is the bright area of the field of view, you will need to ensure that the camera is metering the required settings on the bright area – you will need to reduce the aperture opening (make the f-stop number higher). If the focus of your image is in a dark area of the field of view, you will need to increase the aperture opening (make the f-stop number lower).

Next month, we look at contrast ranges, and overexposure.

spacer
            image