I had been photographing for years before I learned how simple the inner workings of a camera really are. Sure, the digital age has seen to it that our camera bodies are packed with processors, sensors, batteries, wifi capabilities, GPS trackers, and a whole mess of other neat features, but at it’s innermost core, the camera is a very, very basic instrument.
Written about since antiquity, the most basic camera is commonly called a camera obscura, and it is nothing more than a box or a room that only lets light in through one small opening.
When this is achieved, the only light that enters the space travels through the opening, and is projected onto the opposite surface because light that enters only travels in straight lines. Much like how the night sky is far more visible in the country and away from light pollution, by closing off all other entry points for light, the one left open appears to shine all the more bright.
To see an image inside a camera obscura, a person must sit in it for a good 30 minutes if they hope to see anything impressive. After about five minutes inside, the eyes adjust and points of high contrast (like a tree against a sky) become easily visible. After ten, other slightly more intricate objects reveal themselves. Though there is a limit to how good the image gets inside the camera obscura, the longer you wait, the better. Also despite the human eye’s dynamic range limitations, color and motion do become visible as well!
Secondly, the image given is a little deceiving because the image revealed in real-time appears upside-down and backwards. This happens inside your camera as well and it is due to the fact that all light entering the room has to pass through the same hole (what is known as an aperture in a camera). Consider the following diagram:
Looking at a cross-section of a room, it is easy to see how the light reflecting off the top of the tree, represented by the orange arrow, has to pass through the aperture and ends up on the floor. Likewise, the light reflected off the base of the tree, represented by the blue arrow, enters the room through the same aperture, and ends up on the ceiling. The diagram shows how this occurs vertically, and as you might expect, the same happens with the horizontal axis.
Do yourself a favor and don’t take my word for it, I highly encourage anyone to try this experiment out for yourself. It is fun and fairly easy to do.
This is what a camera is in it’s most basic form: a small (sometimes tiny!) box with a hole in one side.
The only difference is that where a camera obscura projects entering light onto a plain wall, modern cameras are designed to record the light that comes in onto a medium. Not too long ago, it was most common to use a light-sensitive film on the inside. Today, a digital sensor does the same job over and over again.
The beginning of this chapter may be a little theoretical for those who are in a hurry to get to the button pushing (I know I would be) but the reason I bring it up, as cursory as it is, is because I wish I had known it when I started taking photos. Learning about photography means learning about light, and the more you know about light, the more informed your decisions will be when you are behind the camera. It’s a lot less about the buttons than you’d think.
Despite the increasing rate of technological developments in the camera industry (which I welcome), quite literally nothing has been around longer than light. As a result, I’m convinced that no amount of breakthrough is going to replace what will happen when a camera is placed in the hands of someone who understands how light works. In fact, I know it will only make those who actually know their light better at what they do.
There is no quick-fix substitute for the knowledge that we will be working our way up to, so for now, let’s get one step closer to using our camera by learning the parts of the Digital Single Lens Reflex camera, the DSLR.
I’m only going to point out a handful of the DSLR’s parts – the ones I think offer the most insight to how light works.
What do you suppose is the first question people ask me about my cameras when I’m on a shoot? I’m sure you could guess, it happens over and over. Go ahead……. Guess……….. Last chance…………………….. Megapixels. “How many megapixels does it have?” is the question I am asked time and time again. Whoever the world leader is in marketing for megapixels isn’t getting paid enough, I can tell you that, because that’s all the consumer-level buyer seems want to know about a camera, and all the shark-tooth-necklaced guy at Best Buy wants (knows?) to tell you about.
Though I do remember a time when the answer to that question mattered more, there are far more important specs to consider these days because resolution has become substantially less expensive. As a result, the jump from 18 to 20 MP has a whole lot less impact compared to when cameras were jumping from 1 to 3.
Case in point, if you’ve got a halfway current cell phone, there’s a good chance it takes a images with a comparable, if not better resolution than a pro level camera (we are talking Super Bowl sideline quality) 10 years its senior. Given the choice between the two, would I reach for the cell phone? Never. Of course I wouldn’t walk around all day with a pro-sized camera body crammed into my pocket, either. Clearly they both serve valuable purposes, but what I’m getting at is: the megapixel rating is not what would make me grab one over the other.
Because photography is all about light, what matters most is what affects the light, and megapixels, (very) generally speaking, don’t have that great an impact!
So what does? Take a look at the diagram below.
Shortly after it enters and passes through the lens (more on that to come) the light bounces 90 degrees vertically off of the mirror and to the pentaprism where it gets turned around and put out to your eye through the viewfinder.
At this time, the mirror is down, the shutter is closed and the sensor, which will record the light, is not receiving any.
When the shutter-release button – you know, the button that makes it go “click” that’s been on the top right side of the camera since the dawn of time – is pressed, the mirror swings up to a horizontal position to allow the light to pass straight through as the shutter makes a carefully- timed opening (called shutter speed) for the light to hit the sensor. When your mirror swings up, the viewfinder will go black for a split second because the light coming in the lens fails to make it there as it passes under the now- horizontal mirror.
Sure, nobody walks into the camera store and says “I want the one with the best pentaprism!” but these are integral parts of the DSLR that not only differentiate it from point-and-shoot cameras, but they enable you to know your camera better, and more importantly, how it physically handles light.
Personally, what would make me grab an old DSLR over a new smartphone is primarily the size of the sensor.
Without being overly technical, the sensor is what collects light. The bigger the sensor, the more surface area light has to fall on, resulting in a better quality image. If photography is all about light, what could be more important than the sensor? Virtually nothing.
I say virtually because what lens is in front of that sensor has a lot to do with how much light ever gets to it, so keep that in mind: Lenses and sensors are team players.
For a visual reference, see the diagram below that compares the not-to-scale sizes of common sensors.
The bigger they get, the more expensive they are. Professionals commonly shoot on 35mm full frame sensors at least, like the one in the Canon 5DMarkIV, and smartphone camera sensors are represented by the smallest ones shown. Medium format cameras which use the sensor at the top, produce the highest image quality but are cost-prohibitive for most photographers. In the end, weighing out what is needed and/or can be afforded is what will push that decision for consumers. Most get by happily with the APS-C sensors, like those found in the Canon Rebel series, because they offer good quality at a reasonable price. Professionals may want to set their images apart, which is usually what prompts them to seek out a full frame camera for higher quality images. Because they make money with their cameras, the cost is more justifiable than it would be to the average consumer.
These are the important internal parts of the camera. As previously mentioned, the most crucial external part of the camera is the lens.
I feel the need to start this part with the tone of an anonymous support group. “Hi, I’m Dan (Hi Dan), and I’m addicted to buying lenses.” Now that I’ve got that off my chest, the detachable lens is what is most notably differentiates your DLSR from a point-and-shoot, and boy, do they matter!
Believe it or not, good lenses are a better investment than a camera body. Taken care of well, they can last a user through multiple body upgrades because the technology does not improve substantially from year to year. What can improve when particular lens models are upgraded are either parts that will improve how fast or accurately it will focus, if it has image stabilization capabilities (IS on Canon, or VR, standing for vibration reduction, on Nikon), those mechanisms can be improved, or details of image quality, like sharpness, or lens distortion, or vignetting can also be improved. As with anything, you get what you pay for, and if you can get yourself a very nice lens to begin with, the potential for it to be vastly updated in the future will remain fairly low.
That said, all lenses are not created equal.
There are two major families of lenses: zoom lenses and prime lenses, sometimes called fixed lenses. Zoom lenses can change their focal length and prime lenses cannot. What this means is that if there’s a prime lens on your camera and you want something in your frame to appear larger in it, the only option you have is to move your body closer to it. With a zoom lens, twisting the zoom ring on the camera will give you the same effect as walking nearer with the prime.
Focal length is measured in millimeters (mm) so a zoom lens would have a range printed on the side, such as 18-55mm or 70-200mm, whereas a prime would only have one number, such as 50mm or 85mm.
You might be wondering, “Why would anyone buy a prime lens? They seem so much less convenient!” That definitely crossed my mind at some point early on. I had friends that were very talented photographers that shot entirely with primes and I couldn’t help but think “why are they doing it the hard way?”
I found out, as is true in life, the hard way usually carries some advantage.
One major advantage of primes can be the price. Pound for pound, they’re generally cheaper than zooms. Another big selling point is that they tend to deliver a sharper image. The third and most compelling advantage, in my opinion, is that they almost always offer wider, sometimes significantly wider, apertures.
The aperture is the size of the hole that lets light through the lens and is shown in the image below. As focal lengths are measured in mm, apertures are measured in f-stops. A high f number, such as f22 indicates a very small opening, and a low f number, such as f1.2 indicates a very large opening. Those particular numbers, by the way, are pretty much the gamut for apertures. Below is a visualization to help with the conceptualization of the numbers.
Each time you “stop down” (close the aperture, increase the f number) or “stop up” (open the aperture, lower the f number) the amount of light that pass through it halves or doubles, respectively. It is because the apertures are circular that the f numbers don’t just simply multiply by two when the light does…. Remember math!? Diameter formulas n’stuff? My skin is crawling already, let’s move on.
So why would one want a wide aperture?
Wide apertures have two main attractions: they let in (sometimes lots) more light, and they narrow the depth of field.
Letting in more light has a direct impact on shutter speeds, the relationship of which will be discussed in my article on exposure, but for now, let’s settle on the advantage that it allows you to shoot well in darker environments (ever get a blurry-looking shot while shooting in a dark place?).
The depth of field, on the other hand, has the powerful ability to direct the viewer’s eye.
One thing that I always want in my photography is for my work to be appreciated, to be liked. To ensure that, I want everyone who views it to have a similar experience and there’s a number of techniques I employ to control that experience. More on that in the post on composition, but concerning focal plane, consider the image below.
Where does your eye go? It rests on the leaves in the middle. Why do you think it doesn’t go first to the ones outside the bowl? Even if you choose to look at them, your eye gravitates back to the middle very quickly. I’m not a mind reader, but it’s easy to say because they are outside of the focal plane and as a result, your brain is not so concerned with them. A wide aperture allows for this blur to happen more suddenly. With a narrower aperture, we might easily become distracted by those extra leaves and drawn away from what’s intended to be important or prominent in the image.
That’s what you’ll get with primes that you won’t get (at least as cheaply) in zooms, and most people would describe this look as “more professional,” even if they can’t articulate why.
And why is that accurate, really? Average consumers don’t typically have prime lenses because they don’t come in the bundled kits that are sold. Most people assume the kit a camera company puts together will be good for them. They might see that the body comes with two zoom lenses, an 18-55mm and a 55-250mm and think “Great, I’ve got such a huge range, I’ll be able to capture everything!” What is often unrealized is that those lenses are cheap because their apertures are very small (read: a hassle) and will be hard, if not impossible to use indoors without assistance from a flash or very high, quality-limiting ISO.
For me, this is the what the importance of primes boils down to: they will set your images apart from the crowd, because the crowd is getting fed cheap zooms.
No problem, you say, what about using the flash? It’s right there, it pops right up automatically!
This is a topic for a future post dedicated to lighting, but consider the following: Where was your flash in relation to your lens on your cheap-o point-and-shoot that you wanted to stop using and get a DSLR? About an inch above your lens, maybe a little offset. And how big was it? The size of a postage stamp or smaller.
Same questions: When your DSLR’s flash pops up, where is it in relation to your lens? And how big is it?
Same answers: About an inch above my lens, and the size of a postage stamp or smaller.
Do you make the correlation? Since light is everything in photography, the same light source will produce a same-looking image. Why’d you spend hundreds of dollars on a camera that has far better capabilities if you’re going to take pictures in a way that produces the same results as a cruddy little point-and-shoot? (Answer: because nobody has taught you any better…until now).
Read my letters: if you want to improve your photography, close that pop up flash and never open it again. I’m not even joking. Not even a little bit.
If that causes you to need more light, solve your problem the better way, by getting a lens with a wider aperture so more light can join the party on your sensor. Short on cash? Get yourself a prime. For the sake of saying, you could also get an external flash relatively inexpensively and learn how to light off-camera, and though I recommend doing that in addition, that of course takes far more time than going out and buying an inexpensive prime.
Have I owned prime lenses that cost nearly $2,000? Yes. More than one, but some can also sell for as cheaply as $125. Prime, or Fixed, doesn’t necessarily equal cheap, but it certainly can, and all beginners should cash in on that.
Besides zooms and primes, lenses have another delineating parameter called their field of view, that is measured by focal length (mm).
Broken down into ultra-wide, wide, mid-range, telephoto, and super-telephoto, these are classifications of particular millimeters. For example, the field of view of a 14mm lens is considered ultra-wide; a 24mm, wide; a 50mm, mid-range; a 135mm, telephoto; a 400mm, super-telephoto.
I would choose my lens based on what I’m using it for. If I want to go shoot wildlife photography, I’m not getting an ultra-wide out. The bird I want to capture will flit away because I’ll have to be too close (inches!) or worse, the bear I want to capture will maul me to death.
Landscape is the opposite story, you won’t get much of it in the image with a super telephoto, but you definitely will with an ultra-wide!
Shooting people? Generally, a head-shot looks best on the longer end of the mid-range and through the telephoto range. This is due to an effect called lens compression that tends to make our favorite features (primarily our noses) a little less prominent.
As a side note, this is why real-estate listers often use wide-angle lenses: they make small rooms look much bigger.
Field of view is a pretty straight-forward science. If you want more “space” in your shot, use a wider lens, if you want less, use a telephoto.
I hope this gets you off the launch pad. If I haven’t turned over a stone you were hoping I would, or worse, dropped a new one on you that went too far, leave a comment below and I’ll write another post or edit this one to clear things up!
What’s next? Exposure Essentials: getting it right every time
**If you’re interested in treating these posts as a self-study with assignments, you can get our Assignment Series 1 question pack to help you learn these ideas through real, targeted, hands-on practice. The Assignment Series 1 question pack is included with enrollment in our beginner’s course.**
