Camera modes

Now that we know the effects that every setting has on our image, we're going to learn how to tweak those settings in our camera's menu. It is possible that your camera has a different menu system but usually all DSLRs have the options I'm going to talk about.

Auto: Not much to say about this mode. It is fast and useful for the times where you just haven't got the time to think about the settings. The camera makes all the decisions about the exposure and even the metering modes, but now that we've learned how to use every of those settings, we want to have control over them, right?

P mode: This one is similar to auto mode, you set the ISO and the camera will automatically set the shutter speed and aperture for the shot. Also P mode allows you to control the metering modes, something we will talk about in future articles

Shutter Speed priority: This is were we start to take control of the settings, this mode will allow us to set the shutter speed and ISO we want and the camera will adjust the aperture to match the available light. Very useful for taking action shots or for playing with motion like we saw in the article about Shutter speed.

Aperture priority: This mode allows us to control aperture, and ISO while the camera will take care of adjusting the shutter speed. This mode is very useful for taking control of the depth of field like we saw in the article about aperture.

Manual: This is the mode, where you control everything. ISO, shutter speed, aperture, metering modes, white balance... .This might sound like it's the ultimate mode to use once you understand every setting, but in my opinion this mode makes it too difficult to get a correctly exposed shot, since it will be you that will have to tweak every setting until you get the correct amount of light. There are moments though where this mode will be the only option, like when you want to use the bulb mode of your camera. This mode allows you to have the shutter open for as long as you want and can be helpful for making very long exposures, like in star trail shots.

So, you will be asking yourself, which mode should I use?

The answer to this question depends on your skills and the situation you're in, as i said before you can use auto mode if you want to take a photograph quick without losing time on adjusting the settings, but the rest of the modes will give you more control over the shot.
I personally find myself shooting usually with P mode that allows me to control the ISO so that the camera doesn't accidentally bump it too high ruining the shot because of the noise. When i want to use some of the exposure settings creatively I just go into aperture or shutter speed priority mode, since they're much easier to use and will give you identical results to the manual mode.
Sometimes you'll just need to use the manual because the camera won't be able to get the shot exposed like you want. Don't be afraid of using it now that you know what every setting does, do keep in mind though that it will probably take some time to get the shot properly exposed. But hey you're doing this just for fun right? Just take your time and enjoy experimenting!

Mastering the Basics: Understanding Aperture

After having learned about shutter speed and ISO settings, now we're going to take a look at the aperture.

The aperture setting is the size of the opening in the lens.

Every lens has a couple of blades, called iris, that are put together to regulate the light that gets through, depending on the aperture setting used.

The aperture is indicated in the camera as the f number. A high f number will represent a small aperture while a small f number will represent a big one. This might sound counterintuitive but is easier to understand if we imagine the f number in the formula 1/f. The higher the f number the smaller the end result.

But enough with the technical details, what is aperture good for?

Tweaking the aperture settings will not only control the light intake, but will also control the size of the depth of field (In short, the depth of field is the part of the image that is in focus). This will allow us to use the depth of field that we find appropiate for our shot. Imagine for example that we are taking a portrait picture. We want everything in the background to be out of focus, so that it doesn't distract from the main subject. In order to achieve that we will use a small f number, that will result in a big aperture, creating a shallow depth of field.
If we were shooting a landscape for example we would do the exact opposite so that all the parts of the image stayed in focus.

The maximum aperture setting will depend from each lens and is an important factor to have in mind when buying new gear, prime lenses, those without zooming possibilities, are the ones which allow higher apertures. It is easy to find cheap prime lenses allowing for f1.8 apertures and more expensive ones even allow for f1.4 or f1.2. Zooming lenses instead have smaller apertures and their maximum aperture varies depending on the focal length used. The 18-55mm kit lens from the D40 for example will allow for a f3.5 aperture at 18mm but only f5.6 at 55mm. Zooming lenses with bigger apertures are only found in the professional level and are used by sport photographers for being able to capture fast shots even in low light.

Summing up, rising the aperture setting will let in more light while making the depth of field smaller and the maximum aperture depends on the type and the quality of the lens.

Mastering the Basics: The Exposure Triangle

Before we go into more advanced aspects we have to master the basic aspects of photography. The first concept to understand is the exposure triangle.

The exposure triangle is a representation of the 3 settings that will determine how much light reaches the camera sensor.

It consists of three elements.

ISO: The sensor's sensitivity to the light
Shutter Speed: The amount of time the sensor is exposed to light.
Aperture: The size of the opening in the lens that lets light in.

An easy way to understand this is to imagine a hosepipe: The aperture is the width of the pipe, the shutter speed is the time the pipe is open and the ISO setting is the pressure.

As you can imagine from the example above, there are several possible combinations that will let in the same amount of light, like for example increasing the shutter speed and then compensating that by decreasing the ISO setting, something common for night shots.

When we use the auto mode of our camera, it will automatically chose a combination to let the correct amount of light in, but while the amount of light will probably be correct, the combination used may not be the best one to get the results we expected from the shot. This happens because each of the combinations has its advantages and disadvantages that will depend on how and what we're shooting. If we want to be able to chose the combination of settings ourselves we will have to take a look in greater depth to each of the three settings: ISO, shutter speed and aperture, which we will do in the three upcoming articles.