Photography: What I've Learned, Part 1
2010-01-01
I’m home sick for the second day in a row with the worst cold I’ve had in years. Blood is leaking out of me, I actually bought medication (something I never, ever do) – it’s not good. That said, as long as I have a blanket, a drink, some music, and a shower and bed nearby, I’m pretty much operational, so I think I’ll pass the time writing up just about everything I’ve learned in my first two months trying to pick up photography.
First, let me say this: I’m improving daily, and yet in absolute terms I’m not particularly good yet – I may never be! That said, I’m a hundred times better than I was the day I got my camera. This means two very important things. First, taking decent pictures isn’t all about the camera, but second, taking decent pictures doesn’t require an excessive amount of knowledge or practice either (note that I said decent pictures, not GREAT pictures – that absolutely does take dedication and talent).
I’ve found my assumptions, and my general understanding, have flowed in sequence from believing that the camera was important, to believing the lenses were important, to believing the light is important. In truth, each is important in its own way, but the camera itself certainly receives far more attention than it deserves! That said, for some kinds of pictures, it certainly does help – you’re not exactly wrong to think “what I really need is a better camera”.
So, let me outline a few technical things, and then I’ll try to use those to explain what simply having a better camera will do for you automatically, and then what a bit of knowledge can do to take things to the next level.
It all begins with exposure. For any given scene, there are three things that control your exposure: the amount of time your shutter is open, the size of the opening in the lens that the light is actually going through (the aperture), and the sensitivity of either the digital sensor or the film (the ISO speed). Some simpler cameras will hide some of these details from you, but every single camera deals with precisely these three things.
One more thing: you can, of course, simply add or remove light from the scene as well, but sometimes that just isn’t an option, and sometimes the only option is your built-in flash, which it took me 24 hours to learn is ugly, ugly, ugly, and 48 hours to learn to not even feel like a snob for saying so. So let’s first discuss the pros and cons of each method of controlling the light we do have, instead.
Shutter time (sometimes abbreviated T or Tv for Time Value): this one is the most obvious. The longer the shutter is open, the more light gets in. The downside is that the longer the shutter time, the more time things have to move around, causing your images to blur (at least, this is usually a downside, although some artistic shots may favour some motion blur, eg. waterfalls, or helicopter blades). Even people that try to stay still will move a little bit. On a windy day even grass and trees can move. And sometimes you’ll want to catch action shots – sports, people mid-conversation, etc., which will demand an extra fast shutter speed. Even if everything else is perfectly still, your own hands will move if you’re not using a tripod!
Aperture (abbreviated A or Av): at a glance, this one seems easy as well – the bigger the opening in your lens, the more light comes in, the brighter your picture. However, there are a few factors that confuse and complicate this. Most simply, unlike shutter speeds, you can’t just increase this value as much as you want. Lenses have a diaphragm that can shrink the opening as much as you’re likely to want, but on the wider side, lenses have physical limitations, and lenses with wider openings are bigger, heavier, and more expensive. Second, aperture controls one other very important thing besides the amount of light coming in – the variety of angles that light can enter at. What this ultimately means is that the wider the opening, the narrower the depth of the area you can keep in focus. You always focus for one depth – that’s what focus IS, really – and things closer to that depth, or farther from that depth, are out of focus. The wider the aperture, the more quickly things will lose focus. This might sound like a bad thing, but it is a huge help in bringing your viewer’s attention to your subject, and many portraits and macro shots are specifically arranged to take advantage of this. Blurry backgrounds are often a good thing to be sought after – there’s even a name for it, “bokeh”.
Next, a list of ugly, inconvenient, and (somewhat) optional facts that ultimately explain why smaller numbers are brighter than larger numbers, and why each incremental step on your camera, while letting in a consistently larger or smaller ratio of light, results in an inconsistent jump in the number given – that is, f/1.4 is twice as bright as f/2, but f/2.8 is twice as bright as f/2. Ultimately the system we use hides these details from you, so long as you know that dialing this setting up or down on your camera will adjust the light consistently, even if the numbers don’t seem consistent. If you want to know what’s going on though, here it is:While strictly speaking, aperture is a measure of the size of the opening in the lens, what we actually care about (and what every camera, every piece of software, and every photographer will always give you) is actually technically something else: the ratio of how wide the opening is, to how long the lens is (this is called the focal length – more on that later). A larger focal length means a more “zoomed in” picture, which means you’re capturing light from a smaller piece of your field of view, which means less light entering your lens. At the same time, the wider the lens opening, the more light you have. Since what we really care about is just the total light, we measure the ratio of these two things, so that we can set this value on any lens, and know that it will result in the same exposure regardless of how long of a lens we’re actually using. Everyone calls this value the aperture, but it’s more properly called the f-number, and sometimes the value will be distinguished by having an f or f/ in front of it, for example f/5.6.The way this ratio is actually calculated is by dividing the focal length of the lens by the width of the opening. What this means is if you have a lens with a 50mm focal length and a 10mm opening, the aperture value you’ll be using is 50mm/10mm = 5. Double the width of the lens, and 50mm/20mm = 2.5. In other words, a smaller number, not a larger one, reflects a bigger aperture, and will make for brighter photos.If you recall your geometry math classes, the area of a circle is pirr. This means that when you double the width (from r to 2r), the area of your circle is now pi2r2r, which can also be written as pirr*4. In other words, doubling your width actually quadruples your surface area, letting four times the light in. So f/2.5 isn’t twice as bright as f/5, it’s four times as bright! ISO speed: with both film and digital, if you can’t actually bring more light into your camera, you can change the light-sensitivity itself. With film cameras, this would involve physically having to buy, and swap, your film. With digital, it’s just a touch of a button to change the sensitivity, at least within whatever range of sensitivities your camera can handle. With both film and digital, the only problem with increasing your ISO is that your pictures will start to get “noisy” or “grainy”, sort of like how turning up the volume to listen to a very quiet song will often produce some background hiss. The ideal solution is more light to begin with (or for that song, more sound going into the microphone that recorded it), but sometimes that isn’t possible.
And that’s it. ISO, shutter time, aperture, these three things will control the exposure, and thus the brightness of your photos. When your camera is shooting in automatic modes, it is coming up with a balance of these three things automatically. You can give most cameras a hint of what you’re trying to do to help them prioritize differently, too. If you pick a “sport mode”, your camera will make sure you have a faster shutter speed, say 1/1000th of a second instead of a more typical 1/100th, so that your fast-moving subjects won’t blur. It will have to up the ISO, and thus the noise levels, to compensate for this, but that’s what must be done (a blurry photo is much, much worse than a noisy one). If you’re shooting in landscape mode, the shutter time can be slowed down, and you can use a lower ISO and a narrower aperture, making a sharper picture with less noise. Shoot in portrait mode, and the aperture will be kept wide open, blurring out distracting background objects and bringing the attention to your subject.
So, what does a quality camera do that a simple point-and-shoot doesn’t, that will make your pictures better right off the bat? Well, first, you might already have a “faster” lens (a lens with a larger opening, that lets light in more quickly), and if you don’t (entry-level kit lenses probably won’t) you might be able to buy one later. Second, the camera probably has a wider range of ISO speeds, and less noise at those higher ISO speeds than a point and shoot. This technology is always changing and improving, but at all points in the technology’s history, physically larger sensors have had better noise performance, and DSLRs have larger sensors than point and shoot cameras. The problem is that larger sensors require larger lenses, to focus light onto that larger area, and so there is a constant tradeoff between the bulk and expense incurred with larger sensors, compared to the gain in image quality. Most high-end DSLRs have a sensor the same size as 35mm film. Entry level DSLRs (like mine) have a smaller sensor size, but are still compatible with lenses meant for larger sensors – you just lose a bit of the image that the lens brings into the camera that is hitting outside the area where the smaller sensor physically is.
Another key difference: a “good” camera will have faster autofocus systems. When you push the shutter button and nothing happens, it’s trying to focus. A camera with more, better AF sensors will help this, and so will giving your camera’s sensors more light, either by brightening the scene or opening the aperture.
The last difference that stands out to me: faster rapid-fire speeds. When there is a lot of action happening, or when dealing with moving people, which our brains are very precisely tuned to carefully scrutinize, being able to fire a bunch of shots at almost the same time will help you capture the decisive moments of interest, where the bat is hitting the ball, or the smile is its widest. Today’s DSLRs start at about 3-5 frames per second, with high end ones up to 8-12. Meanwhile point and shoots might not even have the ability to take two pictures in a row without stopping to re-focus.
Lastly, “good” cameras will give you more precise controls. Perhaps you can focus manually. Perhaps you can switch from a focus-and-lock mode to a continuously-adjusting focus mode. Perhaps you can save your pictures in RAW format, capturing 100% of the detail the sensor recorded, instead of JPEG, which compresses the image, losing detail in exchange for smaller file sizes and compatibility with pretty much every computer program on earth. Perhaps you can manually set any combination of your shutter speed, aperture, and ISO rather than letting the camera take guesses for you on all three. Perhaps you can tell your camera what kind of light you’re shooting in (sunlight, shade, camera flash, tungsten lights, fluorescent lights, etc.), and have it adjust the colour balance of the shot accordingly. And yes, your camera might have a higher megapixel count, but this isn’t necessarily the case, and generally isn’t as important as advertisements in the point-and-shoot market would have you believe.
That’s just about it for the technical side. Right off the bat, your “good” camera will probably focus faster (maybe even more accurately), it will probably take shots quicker, and it will have less noise in the pictures it does take at those low-light, high-ISO settings. On top of that, the better low-light noise performance means you’ll be able to take more shots without using the integrated flash, allowing light to hit the subject from more natural angles, creating softer, more pleasant, more flattering shadows, and eliminating red-eye. That’s the camera. But, like I said at the beginning, it isn’t all about the camera. Bright natural light, and the noise levels aren’t as big a deal. Still subjects like landscapes, and the better autofocus and faster burst-shot rate aren’t such a big deal. But there are other things that can improve these photos! So next up will be lenses… but I think I’ll save that for another day.
Updated Nov 07, 2020 10:29:59am
Feb 28, 2012 4:31:50pm