g Text Version
Beauty & Self
Books & Music
Food & Wine
Health & Fitness
Hobbies & Crafts
Home & Garden
News & Politics
Religion & Spirituality
Travel & Culture
TV & Movies

Bored? Games!
Take a Quiz
Rate My Photo

Autism Spectrum Disorders
Mental Health
Blogs / Social Networking
Kidney Disease
Today in History

All times in EST

Full Schedule
g Photography Site

BellaOnline's Photography Editor


How to use a Lightmeter

Guest Author - Kaye Barnett

A light meter is an essential tool in photography to ensure properly exposed photographs. Certainly all digital cameras today will have them built in and use them to measure the amount of light and ensure a properly exposed photograph. This first article takes a look at lightmeters in general.

Light meters use a special cell, or photo sensor made from either selenium, silicon, or a photo resistor made from CdS - a cadmium sulfide resistor that is also found in electrics of street lights which decides if they should be turned on or off!

A photo sensor made from selenium or silicon is able to power up when light is available to them and the selenium and silicon cells generate their own electricity from the light.

With a photo sensor made from selenium of silicon, the amount of electricity produced by the cell depends upon the amount of light there is. If there is plenty of light, the cell will produce a lot of electricity and if there isn't much light then the photo sensor won't be able to produce as much electricity. The amount of electricity produced is how light is measured.

But CdS photo resistor works a little differently, it can't generate it's own electricity but instead works by varying the amount of electricity that passes through it, and this is dependant on the amount of light there is. So, if there is lots and lots of light the CdS cell creates a minimal amount of resistance and therefore conducts electricity very well. If there is not much light at all then the cell has a high resistance, meaning that it doesn't conduct electricity very well. This variation in the amount of resistance created by the CsS cell is how light is measured on a light meter.

whether it's a selenium or silicon cell generating electricity from the amount of light available, or a CdS cell controlling the amount of electricity in light, these results need to be displayed! To do this we connect the electricity to a meter read out. In it's simplest form, the result is displayed using an analogue meter; a needle over a scale, where you can watch the needle sway backwards and forwards with the varying light and rest on the given reading. More commonly nowadays light metering results are displayed on a modern hand-held digital read-out, typically a meter with all sorts of sophisticated computerised extras! And similarly with built-in camera meters the computer on board inside the camera processes the information to determine the correct exposure based on the settings you’ve chosen to work with.

Handheld Lightmeters

There are a couple of different hand-held light meters available and each measures light in a slightly different way. These different meters will measure either reflected, or incident light. you can also get meters that can do both! For more information on how the differences of these two light meters, and how they work visit this article on the Photography site.

Add How+to+use+a+Lightmeter to Twitter Add How+to+use+a+Lightmeter to Facebook Add How+to+use+a+Lightmeter to MySpace Add How+to+use+a+Lightmeter to Del.icio.us Digg How+to+use+a+Lightmeter Add How+to+use+a+Lightmeter to Yahoo My Web Add How+to+use+a+Lightmeter to Google Bookmarks Add How+to+use+a+Lightmeter to Stumbleupon Add How+to+use+a+Lightmeter to Reddit

The best printer for your digital camera
Converting photos to Black and White using Photoshop
How a digital camera compresses photos
Editor's Picks Articles
Top Ten Articles
Previous Features
Site Map

For FREE email updates, subscribe to the Photography Newsletter

Past Issues

Printer Friendly
tell friend
Tell a Friend
Email Editor

Content copyright © 2015 by Kaye Barnett. All rights reserved.
This content was written by Kaye Barnett. If you wish to use this content in any manner, you need written permission. Contact Ewa Sapinska for details.


g features
Zoom Burst Photography Explained

iPad Apps For Photographers

5 Tips For Wide-Angle Photography

Archives | Site Map


Past Issues

Less than Monthly

BellaOnline on Facebook

| About BellaOnline | Privacy Policy | Advertising | Become an Editor |
Website copyright © 2015 Minerva WebWorks LLC. All rights reserved.

BellaOnline Editor