Lets try something. Grab your camera and switch to manual mode. That mode where you can, using the buttons and wheels on the body, change between different apertures, ISO settings and shutter speeds. I know, that may sound like alien, at least it sounded like that to me the first time I tried something a bit more complex than a point and shoot camera. Basically, what those parameters control is how much, and during how long, the light enters in the camera and prints a picture on its sensor (film, for the old-school ones). What that creates is a darker or lighter picture. Also, it will affect to the blurriness of the image, in some specific ways. One thing we have to understand is that there is no perfect exposure¹. Your camera will have some way to show you, in advance, how dark or light your picture will be, but it is only an estimation, based on its metering system. Some people will tell you that your camera has a tendency to under exposure or over exposure but that only happens in the automatic or semi-automatic modes, and that is easy to fix with exposure compensation. We are experimenting with fully manual. And in fully manual you are the one who decides. And the nice thing is that in all the cameras, this mode works exactly the same. Lets start with the aperture. Smaller values let enter more light to the camera than bigger ones. So, if you dial a 3.5 as aperture, your image will be lighter than say, if you dial a 11. But something will change also in the blurriness of the image. For small numbers, the image will have a more blurred look around the point of focus. And for bigger numbers, everything will look sharp across the entire frame. From now, we will call those numbers f-numbers. The next thing is shutter speed. This value is usually measured in seconds, and fractions of a second. It tells the camera to let enter the light for a specific amount of time. Some cameras can get as fast as 1/8000 of a second. That is really fast, and very little light will enter in your camera, so things will look dark. But very sharp. Everything will look perfectly stopped in time, without motion blur. And the last parameter is the ISO value. This measures how sensitive to light the camera is. It is recommend to stick with the lowest values possible. Basically, lower values are darker than higher ones, but the higher ones will make the image to look grainy. And now you may be thinking: How do I guess which numbers I have to use in manual mode for this specific picture I have in mind? Well, there is not a right way of doing this². What now is needed is a better understanding of the relationship between those three parameters and what can you get tweaking them, because each of those parameters affects the others somehow. This works much like a tap with three different valves, and only practice will help. I can give some start: try a shutter speed of 1/100, aperture of f8 and ISO 200. This may work well for a sunny day walking in the town. Try and see what happens. If your pictures are dark, your first fix can be to lower the shutter speed, say 1/50. What may happen then is that people in the pictures are blurred because they move quick. Try then to dial less shutter speed, say 1/200, that will fix the motion blur a bit. Now it may look dark. Lets try now to open a bit the aperture, from f8 to f4. That will let enter a lot more light but maybe now things are a bit more difficult to focus (good for portraits, lees so for landscapes) . Then change the ISO, go back to f 8 and raise the ISO to 400 or 800… In this process, you’ll end with lots of pictures that look too dark, too bright, blurred or not, with more or less grain . Keep the ones you like most, and that is!. Soon, after a few thousands wrong pictures, you’ll gain confidence with this manual exposure mode. As I said earlier, this is a perfect mode for experimenting. For doing decisions about what look do you want to achieve in your pictures. This mode is not always useful, and it is only recommended when you have time to try things. An example where this is useful is when you need to take pictures for a panorama. If you need to quickly grab a snapshot of some place or someone, better use the semi automatic modes, for example aperture priority is very popular and easy to use. With time and experimentation you’ll see what works best for you. I was going to add the usual picture of an exposure triangle, but Google served me this one first:
1.That perfect exposure concept is just that, a very subjective thing that depends on what exactly do you want to show in your picture.
2.This is just for the sake of this scientific experiment, right? 😉