Digital Photography For Beginners - Understanding Exposure

Exposure is controlled by each of these controls differently

. Aperture controls the amount of area exposed to light. Shutter speed controls the amount of time light is let in. ISO governs the camera's sensitivity of the sensor to the exposure. The key here is knowing what settings affect what property of the image. The aperture affects the depth of the field, shutter speed impacts the motion blur and ISO impacts the noise of the image.

Now let us see each of these controls in detail.

Aperture: This control affects the amount of light the lens allows through it. It is measured in terms of f-stop value. Ironically, as the f-stop value increases, the light amount received decreases. For every 50% reduction in the f-stop value, the area where the light is collected increases 400%. So if an f/4.0 f-stop value has a relative light exposed area of 32x, f/2.0 will have an area which is 400% more - 128x.

Generally, compact cameras have limited range of aperture where as a digital SLR camera will have a wider range and hence better control on exposure. And also narrow aperture settings (large f-stop value) leads to greater depth of field which is used in landscape photography while large aperture settings (narrow f-stop value) leads to lower depth of field which is used in macro photography.

Shutter Speed: Shutter speed is the amount of time the sensor is opened to allow the light. And more the time the sensor is opened, more light is captured. The relationship between time and the light is 1:1. In night photography, where the light will be low, the shutter speed should be very less as more amount of light would be needed. And to capture a still image of a formula 1 car, very high shutter speed would be necessary.

ISO Speed: ISO speed, like shutter speed, has 1:1 co-relation with exposure. A lower ISO speed is always desirable as higher ISO speed mostly will result in a more noisy image (more grainy image). Only if the aperture or shutter speed settings can't be set to desired exposure levels, ISO speed should be increased. Compact cameras have a limited range of about 50-200 ISO speed for getting good quality images. Higher than 200 ISO speeds in compact cameras generally result in more noisy images. DSLR cameras produce acceptable images up to 800 ISO speed.

Many cameras have many exposure modes like Auto, Program, Manual, etc. Except for manual mode, most other modes allow 1 or 2 of the 3 controls to be changed and those controls which are not changed are automatically set by the camera itself. Auto mode however manages all the controls by itself. Likewise, cameras will also have several preset modes like landscape, portrait, etc., which when selected, sets the aperture, shutter speed and the ISO speed to the optimum level for that mode.

by: sandz1214

POST COMMENT

Apple iphone 4 32gb store maximum digital data at one place Digital Camera Bags for Women: What Are Your Best Options? Chinese Industrial Biotechnology Industry: An Analysis - Market Research Report On Aarkstore Enterpr Understanding Digital Photo Frames 8gb Mini Digital Camcorder Spy Stick Interview Recorder How To Cross Over To Digital Media Sales Canon EOS Rebel T2i Digital SLR Camera Review Polyester Industrial Yarn, Low Melt Fiber From Fiber Partner Nikon D60 digital SLR Camera Review Outdoor Digital Signage Enclosures - Outdoor Dynamic Marketing To Factory Information System protection Enhance Customer Satisfaction And Improve Quality With Integrated Application Lifecycle Management Go Digital - Digital Hearing Aids That Is Heating And Air Conditioning: Facilities And Systems To Suit All Tastes