A while ago I introduced tripods in BTW, in what was my first technical article about photography. In it, I admittedly did a very forced and messy introduction to the foundations of this art. It’s true that to explain tripods, I should indeed describe those concepts. But the tripod (or any other specific subject for that matter) should come after fundamental photography basics. Which is, alas, what I intend to do now.
There are many types of approaches to learning photography. Some of them start with actual physics to understand light (too theoretical). Others guide you through what a camera can do (too practical). Fortunately, most of them teach photography through the three basilar concepts that influence the light you get in your shots: shutter speed, aperture, and ISO. This was also my way of learning, and I feel it continues to be the best way there is.
You can see them in the picture below. They’re the three numbers shown on the LCD (you have to be in manual mode to see it). You can change those settings either in that screen or use physical dials around the camera. First, though, it’s important that you know what they are and mean. And as important, how they relate to exposure, i.e. how they make your shot darker or lighter.
The time during which the camera exposes its sensor and thus lets the light going through the lens hit it. It can range from 30 minutes (or more) to really fast times such as 1/5000. This latter is the number format cameras use to represent a 5000th part of a second. Yes, they can be that fast! Different shutter speeds will cause different results and effects but, for now, I’ll refer just two important figures: 1/30 and 1:250. A thirtieth of a second (1/30) is the threshold by which you can take a handheld picture without shaking. 1:250 is the threshold by which you can freeze most normal human movements. Logically, these numbers are not binding, but rather averages. Light-speaking, it’s very easy to understand: the longer the shutter speed, the more light gets to the sensor.
The diameter of the opening that the lens creates to let the light enter. Most people spend a lifetime looking at a lens, but not looking beyond the glass. If you look close enough, you can see there’s a set of blades all around the inside of the lens. Those blades move as a group closer or farther from the center, effectively closing or opening the space in the middle (where light travels). Aperture figures have an “F” before their number (as in “F5.6” in the picture above). I’ll leave the meaning of the F and the equation that leads to those values for another article.
What is most important to understand now is that a low F-number leads to a larger diameter and a high F-number leads to a narrow “hole”. Having this knowledge, it’s easy to then transpose it to light: a wider diameter gets more light; a tighter diameter gets less light.
The sensor’s sensibility to light. Clearly the ugly duck of photographic settings, ISO is both a blessing and a curse. Usually, an ISO number ranges from 100 to 12800 and more. These values come from the days of analog photography. Rolls of film have a fixed sensitivity which comes from the silver compounds they are made of. In the digital world, the exact same concept doesn’t exist obviously, but camera sensors still have a sensitivity you can control. As one can assume, less ISO leads to less light, while a higher ISO leads to more light.
The first part of the photography basics lesson is complete. You know what the three essential elements are and how they relate to light. But without more, you wouldn’t know how to change these parameters to take a particular shot. That’s because you don’t know what’s the right amount of light for every situation.
Although you don’t know how to measure light, you can at least understand that pictures can be too dark or too bright (exposure). One basic trick you can do to ensure your light is okay is to take a sample shot and then change the parameters accordingly, repeating that as many times as necessary. Actually, with the information above you should already be able to do this. However, this trial and error (which everyone does sometimes) is a “dumber” version of what you should really do. The proper way to do this is a two-step process: 1) know what is the type of shot you want to get, 2) change the settings in accordance.
And this is when things get tricky. You see, not only you can adapt the three settings to allow more or less light to come in, but every one of them has a SIDE EFFECT to the end results. So photography is not just playing with the amount of light allowed by each setting, but also with the consequences of that amount of light. Shutter speed, aperture, and ISO all have positive and negative repercussions throughout their range of different values.
Shutter Speed – Sharpness
The side effect of the shutter speed is sharpness. If the sensor is quick enough, it can freeze whatever it gets, so you’ll get a sharp picture. If you get to slower settings (more light), you can experience undesired outcomes. The most common of which is moving parts getting dragged across the picture, or motion blur. It means that those movements happened during the time it took to take the picture. The deduction behind this balance is now within our grasp. For most situations, in which I assume you want to freeze action, you’ll want the fastest speed as possible. So you’ll get the least light as possible too. Suddenly it’s not so easy to get light, huh?
Don’t worry – for most outdoor daytime scenarios, you can get enough light while still freezing your shots!
Aperture – Depth of Field
The side effect of aperture is depth of field (DOF). This relates to the depth layers of your picture which the camera will focus when shooting. In other words, how much of the resulting picture is focused. Again, we have a harsh tradeoff regarding light. That’s because apertures with the most light (low F-numbers) give you the least amount of DOF, and vice-versa. Meaning that, if you want focus across your whole shot, you have to use a high F-number, which gives you less light. Therefore, you have to get the light somewhere else (the other parameters) or find a middle ground of values to play with.
And slowly you get what photography is all about: playing with these three concepts. Ultimately this is the most important of the photography basics. This is the reason why people collectively called them “exposure triangle”, i.e. changing one of the vertexes requires a change in the others to restore the original light.
Like sharpness, don’t worry too much about DOF either. Even the lowest DOF can capture a good portrait picture. And for subjects far away from the camera, the DOF will not matter anyway, since there’s a threshold after which everything is focused.
ISO – Noise
The reason why ISO doesn’t get a lot of love is that, unlike the others, its side effect is almost always undesired. That consequence is digital noise. When the sensor increases its sensibility (to get more light), it adds defective pixels (grain) across your shot that gradually deteriorate the quality of its results. It’s what most smartphones, and cameras in automatic modes, do when you’re in low-light scenarios. This is why your night shots are shitty when the same exact device has great results on a sunny day. Sharpness and depth of field, in their whole spectrums, can create interesting visual effects (please check future articles). On the other hand, purposely adding noise to your pictures, albeit an artistic movement of its own, is much less regarded.
In other words, there’s a clear rule to follow here. Keep ISO as low as you can at all times. In any case, there are situations when only an increase of ISO will get you enough light (for example when you can’t touch the other two properties). So ISO can be your last friend to invite to the movies, but a dependable one!
I created the following chart to help people quickly make sense of the aforementioned logic. This sort of “photography basics cheat sheet” is a friendly tool for anyone starting to shoot in manual in order to control most aspects of their results.
One can freely change and combine each one of these properties to achieve particular results. Certainly, you can start by “common settings”, which I would say are: 1) a fast shutter speed, 2) a large aperture and 3) a low ISO. For example 1/400, F4.0 and 100. But whenever lighting conditions make it harder, or your desired effects demand it, you have to get your hands dirty. That’s when these photography basics will come in handy!
I’m definitely more relieved now. The circle has been closed in BTW. I may return to some of these properties individually in the near future. And I may tackle the different effects you can achieve by their different values. But everything else will rely on this article. There are still other subjects which deem an explanation, such as focus types, focal length, white balance, etc. But at the end of the day, most photographers (and me) will tell you that these three pillars are the first things to know.