2: Basic Camera

The Sensor

At the heart of any camera is the sensor. It is a flat rectangular chip that light from the lens falls upon during exposure. It converts this light to numbers which will form an image. Like the back of your eye takes light and converts it into stuff for your brain to figure out to make vision.

The Camera

Just as the back of your eye is pretty useless without all the paraphernalia surrounding it (front of your eye, brain), the sensor chip needs other things, which are collectively called a camera.

There are two types of digital cameras that are controllable and capable of high-quality images. These are distinguished by their viewing systems. The first is a Digital Single Lens Reflex (DSLR or Digital SLR) camera. These cameras are the traditional mainstay of photographers, and they are the ubiquitous type of camera at anything from press conferences to sporting events. They are versatile and generally dependable work-horses. The basic design of DSLRs predates the advent of digital cameras by more than a half-century.

DSLR Camera Operation

With a DSLR viewing system the image from the lens (which forms the image) is reflected by a mirror up into the viewfinder. When the shutter is pressed, the mirror flips up and the image is allowed onto the sensor for the time it takes to record it. After the image is recorded, the mirror flips back down and the image is again diverted to the viewfinder. If you have one of these cameras you can see that the instant the picture is being taken the view-finder is dark.

While this type of camera is very good, it does have some disadvantages. What if the flipping mirror could be eliminated, enabling the camera to be quieter and smaller?

Mirrorless Cameras

The answer is the mirrorless camera. While the name is not too imaginative, it does describe a big difference from DSLRs. These cameras, since they do not rely on a mirror, are indeed both quieter and smaller. They are also somewhat more expensive than comparable DSLRs.

With a mirrorless camera, you are viewing an image made by the sensor when you look at it in the viewfinder. When you take a picture, a shutter closes, blocking light from the sensor, then opens again to expose the sensor, which is now in shooting mode. After the exposure, the shutter closes and then opens again in viewing mode. All of this in a fraction of a second.

Which type of camera is best depends on the photographer. Since the mirrorless camera’s viewfinder is an electronic image, the viewing is very different from viewing the optical image of a DSLR—some hate it and some like it. There are also some other differences in these cameras,  such as how the camera auto-focuses.

Sensor Size

Image quality is largely governed by sensor size. Common cameras generally have what are called APS-C (or four-thirds) size sensors, while more expensive cameras generally have larger full-frame sensors. These full-frame sensors give better image quality, but they might be a waste of money since the image quality of the smaller sensor is darned good. Since the APS-C sensors are smaller, the cameras that sport them are also smaller.

Other Cameras

There are many different types of cameras designed around very small sensors. As a matter of fact, a designer can put a sensor into just about anything. Add a lens, and you have a camera. Cellphone cameras, Go-Pros, and small point & shoot cameras are just a sampling. Sensors and lenses are put in watch-bands, eyeglasses, and even digital assistants which can assess how you are dressed.

Most of these have tiny sensors. The quality of an image is directly governed by the size of the sensor, so if you want the potential for having a high-quality image, you have to use to a bigger camera. This is not to say small sensors cannot take good photographs. They can, but are very limited in how well they can in different situations and for different uses.

Using Your Camera

With most DSLR and mirrorless cameras, you have the choice of composing your photograph either through the viewfinder you put up to your eye or viewing it on the back viewing screen. Which method is better largely depends on the situation and your preferences, but generally viewing through the viewfinder allows you to at least brace the camera better for potentially sharper and more carefully composed images.

There are other advantages to using the viewfinder. The back viewing screen is one of the highest users of power in your camera, so turning it off will conserve your battery. With DSLR cameras, using the back viewing screen to compose your images switches to a slower and less precise auto-focusing method. 

Holding the Camera

In situations with a lot of light, how you hold your camera doesn’t matter too much as long as you can study the image carefully. But when taking photographs in lower light, the possibility of camera shake can make for some really blurry images. If you are using the viewfinder in low light, hold the camera with both hands, tuck your elbows against your body, and press the camera to your face to steady it. Calm your  breath while you squeeze the shutter button. And if it is a really low-light situation, forgo that last cup of coffee.

When using the viewing screen on the back of the camera, is more difficult to steady it, but pushing the camera away from you so that the neck-strap is tight around the back of your neck helps. Neck straps will be discussed very soon.

If you really want to take photographs with very little light, look for a wall or pole to lean against. Even better, find a surface to put your camera on or hold it against.

Neck Strap

A neck strap for your camera is like a seat belt in your car. Use it. Gravity loves to eat cameras.

UV Filter

When you purchased a camera you may have been pressured to buy a clear filter to put over your lens. If you didn’t buy it, consider doing so. Doorknobs seem to love my lenses, and I am sure there are many things just waiting to put a dent on the front of your lens or crash right into the glass. It is much cheaper to replace a filter than an expensive lens. These filters are called something like UV filter since it sounds better than glass filter. They do block some UV (ultraviolet) light, but then again, so does plain glass.

Clean your Friggin Lens

Try this simple exercise: Eat a bunch of potato chips, then put finger marks all over your glasses or sunglasses. Now see how much worse your vision is. Your camera’s vision is very much like this. 

All you have to do to clean your lens is fog it up with a HUH from your lungs, then with light pressure wipe it in a circular motion with a soft cotton cloth. A clean cotton shirt (not the one you were wearing when you ate all those chips) will do. For greasier situations you may need to apply a little eye-glass cleaner instead of the HUH.

Don’t worry if you have a few flecks of dust on or in your lens. If it is in modest amounts it will not effect image quality.

Tripod

When you have very little light, a support better than shaky human hands is needed. Although tables, chairs, and all sorts of other things can be used to steady the camera, a tripod made for this purpose is the most versatile.

Tripods come in all sizes and at all costs, and even a very inexpensive one can get you a good photograph. If you want to use a tripod a lot, though, remember that you pretty much get what you pay for. More money means a steadier support, better durability, controls that securely lock the camera into place, and lighter weight relative to the size of the tripod.

Battery

The battery that powers your camera is pretty straightforward, but there are a couple of things you should be aware of. First, some operations on cameras (like using the LCD screen to view or review images) drain the battery fairly quickly. 

Secondly, cold temperatures will not drain a battery, but will make it powerless until it is warmed up again. In the winter, consider keeping a spare battery in a warm pocket if you are outside for a while.

Rain

One of the reasons photographers buy expensive cameras is that they are often water-resistant. Each door, button, and dial has rubber grommets to protect the insides from a light rain and splashes.

Most less-expensive cameras are not waterproof at all. As your pappy (should have) told you, water and electricity don’t mix, and the inside of your camera is chock full of sensitive electronics. I just found out that spilled beer is also pretty darned good at sneaking into cameras. Keep your camera away from any liquids (beer or rain). I will try to as well.

Controls

Although your camera has dozens of  different settings you can control, there are just four main settings on any camera that influence the interpretation of an image—focus, aperture, shutter speed, and ISO. 

Focus

When you lightly push the shutter button the camera tries to find an area to focus on. When it does, it locks onto that focus (showing the area it picked in a rectangle or oval). If you lift your finger off the button, this focus is forgotten, but if you continue to press the button, the photograph is taken utilizing this focus area.

Aperture

Just like the iris of your eye, a camera has a variable size opening which controls the amount of light let through the lens. This is called the aperture. When you are using the ‘P’ setting on your main dial, this opening is controlled automatically by your camera according to the amount of light present in the scene.

Shutter Speed

Behind the lens, and very near to the sensor, there is a sliding curtain which controls the amount of time light is allowed to hit the sensor. This shutter governs the shutter speed. The time the shutter remains open is expressed in fractions of a second (whole seconds for long exposures). Like the aperture, the camera determines this time automatically based on the amount of light present in the scene.

ISO

The sensitivity of the sensor to light is governed by the ISO setting. The camera can set this automatically based on the amount of light present in the scene. But as mentioned before, you should have it set to ISO 400.

All Together

These four settings (three of which are for exposure) are almost always reported in the viewfinder or on the back viewing screen when you push halfway on the shutter button. They display as a group of two numbers: the first is the shutter speed (in fractions of a second), and the second is the aperture (sometimes with the letter ‘F’ before it). Separate from these, and usually labeled as such is the ISO number. The point of focus is shown as an overlay on the image itself.

A camera makes all of the exposure adjustments based on the amount of light in a scene. But it doesn’t usually make the adjustments based on the subject. The camera is basically guessing what you are taking a photograph of. When you are new to photography, this system works fairly well. But as you get more experienced, you will want to make the decisions based on how you want to interpret the subject.

The Other Settings?

But what about the other dozens of buttons and settings on your camera? These govern many things, such as the file format used (it should be RAW), or the zoom setting that allows you to bring a bear closer without actually bringing the bear closer.

These other settings are responsible for a lot of complexity in your camera. On one camera of mine there are twenty-two menu items with no less than a hundred settings that govern how the camera carries out automatic focus. Yikes! I do not know how to use them all, nor do I need to since most are for special purposes.

There are some expensive professional cameras that actually have very few settings. But all cameras dealt with in this text will have provisions for changing focus, aperture, shutter speed, and ISO.