Good Morning, and welcome back. I was thinking last night how to improve and expand on things I post here, and came up with the idea to do a series of posts titled “Mastering the Basics” sort of a refresher course for photographers and myself in creating these. There will probably be some sprinklings of technical and slang terms in here, but I hope I have explained them well. If you have questions feel free to leave a comment and I’ll work on explaining things further or answering them.
So why not start right at the beginning on how a camera works.
Here are two examples of Nikon cameras. The one on the left is a Nikon F3, the Professional camera from the 1980s, on the right is a Nikon D300, my current main camera. Now the question is, do these two camera work in the same way?
Yes, they do.
One fact that is often lost is that all cameras, from the very first camera to the latest and greatest work on the exact same principle. Light, reflected off an object is directed through a lens or hole onto a light sensitive recording medium, and stored. The only difference is what the medium is and how it’s stored. In the case of the F3, it uses Film, which both records the image and stores it. The D300 using a sensor and then stores the image on a Compact Flash card. Yes, even your point and shoot camera works with these same principles.
Controlling Light. As I mentioned earlier, a camera directs light through a lens onto a light sensitive medium. If you just let all the light into the camera onto the medium you’ll just be seeing white. Lots of white. This is why you need to control the light being recorded. There are three things that do this, they are aperture size, shutter speed, and senstivity.
Aperture controls the amount of light going in, shutter speed determines how long the light is let in, and sensitivity determines how receptive to light the medium is.
Aperture: when you look at an eye, notice how in bright light the pupil goes smaller and in darkness opens wide, the camera’s aperture works in the same way.
When you look at the lens you’ll often see a series of numbers and letters. Of course there’s the 105mm, this is the focal length. But the one that we’re going to focus on is the 1:2.5. This indicates the maximum aperture the lens has, or how wide open it can go, these numbers are called F-Stops they are also written as f/2.5 or f/4. You might also see 1:3.5-4.5, this means that the maximum aperture is variable based on the focal length, this is often found on point and shoot lenses, or lower end zoom lenses. So while at the one end of the focal length you might have a maximum aperture of f/3.5 when you zoom all the way in, you’ll only have a maximum aperture of f/4.5. The lower the number the larger the maximum aperture, so a lens marked 1:1.8 will be able to let in a lot more light than a lens marked 1:5.6, so the f/1.8 lens is called faster. But the more open the aperature is the less of the photo will be in focus, this is called depth of field, which I will discuss in a later posting.
Shutter Speed: The shutter is often a piece of cloth or metal that protects the light sensitive material, the shutter speed determines how long this curtain is open. This speed is often listed in fractions of a second, noted by a quote mark so 1/60″ would indicate that the shutter was open for one sixtieth of a second or 30″ would indicate the shutter was open for thirty seconds. On average a person can shoot at speeds of 1/60″ or faster (1/100″ ect), this eliminates the appearance of camera shake in your images. See the photo below.
This is an example is a little extreme (6.4″ shutter speed), but shows off what camera shake is, most people will see this when shooting at speeds around 1/30″ or slower (1/15″). Of course camera manufactures have been working on new ways to assist by installing Image Stabilization (There are many names for this, Nikon uses VR or “Vibration Reduction”) on lenses or in camera.
Sensitivity to Light: As the name suggests it is how sensitivity to light the medium is. There’s really no real way to explain it. This sensitivity is measured on a scale known as ISO numbers (pronounced Eye-Ss-Oh, not eye-so). The higher the number, the more sensitive to light the medium is. However there are drawbacks to using a higher ISO, you get more grain (or noise in the digital world), this is noticeable aberrations in your images.
So combining aperture size, shutter speed, and sensitivity is how the camera determines how the light is captured. The real trick comes with choosing how to use all three in concert. But that will come with later posts, and a little more about manipulating the each setting to get the look you want.
Tags: cameras, how-to, Photography, tutorial