SLR Camera basics

SLR Camera Basics

by Rachel Opdahl

SLR = Single Lens Reflex – This refers to how your camera differs from a point and shoot.  With an SLR, the image you see through the viewfinder is reflected with mirrors onto the chip inside.  What you see is what you get … because the lens sees the same thing.  With a point and shoot, the viewfinder doesn’t reflect back any image with mirrors…in fact, what you see is not what the lens sees because the viewfinder and lens are not connected in any way.  The viewfinder is just a hole in your camera that sits above the lens.  This can be a problem, especially if you are close to your subject.  For example, have you ever taken a picture with a point and shoot and later saw that someone’s head was cut off?  What you see is not what you get with point and shoots.  However, your LCD screen will be accurate for both camera types.

3 Exposure/light controls.

Aperture:  Controls how much light enters the lens and controls your “depth of field,” or in other words, how much is in/out of focus. Think of how your eye works.  The pupil dilates like the aperture opens and closes.  Is it wide open, letting in more light or barely open, letting in less?

Shutter: Controls how much light enters the lens.  Think of the length of time in between blinks, or how fast your eye lid opens/closes.

ISO: Controls how much light the chip is recording and how “noisy” the file will be.   Lower ISO = less noise + more light needed...not good for low-light situations.  Higher ISO = more noise + less light needed…great for low-light situations. (“Noise” refers to the “little dots” or “blocks of color” that can appear.)  Think of a piece of film…when it has small particles…you can’t see them as easily, but it’s not as easy for the particles to capture the light.  Larger particles easily capture more light, but you can see them.

Circular Dial with: M, Av, Tv.

-Av: Aperture Priority.  You can set the aperture and the camera will set the shutter for correct exposure automatically.  (Also known as “setting your F-stop”).  Why use this?  You can have a “shallow depth of field” or in other words “a nice blurry background."

-Tv: Shutter Priority.  You can set the shutter and the camera will set the aperture for correct exposure automatically. Why use this?  You can freeze or slow time and get those action/motion shots.

-M: Manual.  You will need to set the aperture and the shutter yourself for correct exposure. (Use your camera meter to help with this.) Why do both?  You will really get better exposures and better looking pictures overall!

What’s a meter?  … and my camera has one?

All cameras have a meter to help determine the amount of light that is seen.  When you learn to read and control the meter, you can control the light and exposure.

Above:  Here's a picture of what your camera meter reading looks like when it's properly exposing a picture.  The largest green line is right smack in the middle.  You can either see it by looking into your viewfinder (it's down at the bottom usually) or it is usually on your LCD screen.
To overexpose, it goes to the right.  To underexpose, it goes to the left.  The numbers are your shutter speed, f-stop, ISO speed, and picture number.