To the novice photographer, or the photographer-wanna-be, it seems like the technical terms are a foreign language, one that I can never fully learn. But my goal in writing this to show you that this language is easy to learn. You can learn it too. I am going to cover the basics here, to try and help you understand those terms you hear floating around like “18-55 mm” or “full frame sensor.”
If you are considering the purchase of your first DSLR camera, but don’t understand all of the technical stuff, read this first.
Let’s start with the basics: The Sensor:
In the olden days of film photography, the image was formed by the light hitting the film. Today, the light hits the digital sensor to create the image. The size of the sensor has a very big impact on the quality of the image. The larger the sensor, the better the quality of the image.
Image via Wikipedia.
Most high-end DSLR cameras have what is known as a 35 mm, or full frame sensor. Entry and mid level DSLR cameras mostly have what is called a cropped sensor. A cropped sensor is slightly smaller than the full frame sensor, but still about 5 times the size of the sensor on the average point and shoot camera. In the diagram above, the green or orange small boxes would represent the sensor size on a point and shoot camera. DSLR sensors are marked in the larger boxes.
The result of the sensor size on image quality isn’t important to this post, but the sensor size will be in issue in two areas, so pay attention to this!
There are two main reasons issues where the sensor size will come into play. Firstly, the sensor size will determine which lenses will fit on the camera. There are plenty of exceptions, but here’s the basic rule: most lenses will fit on a camera with a cropped sensor. However, not all lenses will fit on full frame sensor cameras.
Bottom line: if you are buying a lower-end DSLR, you most likely won’t need to worry about this. If you are thinking to upgrade, read up on this more before purchasing additional lenses.
There’s another reason that the sensor size is important, but I’ll explain that after we discuss Focal Length.
Next, let’s talk Focal Length:
Focal point refers to the image that you “see” through a particular lens. This is the main number that you hear pop up in lens discussions- i.e. “I am shooting this with my 100 mm lens.”
What does it mean?
Let’s start with a reference point. The approximate focal length that you see with the naked eye is 50 millimeters (mm).
Anything lower than that will be a wider focal length. Anything higher than that will be a narrower, or closer focal length.
Wide Angle: Say you are in an auditorium with a large number of people, and you want to capture as many of them at a time as possible in your image. With the naked eye you can see a certain portion of the room, but with a lower focal length lens, such as 24 mm, you can get a wider view of the room.
Telephoto: Imagine you are vacationing near a mountain range, and you want to get a photo of a mountain top off in the distance. While your naked eye might see it surrounded by other mountains and various scenery, with a telephoto lens (one with a higher focal length than 50 mm) you can get a close picture of just the mountain top. Conversely, if you want to get the entire mountain range, you will want to use a wide angle lens (see above).
Let’s make it all visual, shall we?
Here’s a picture taken at 55 mm, or approximately what you would see with the naked eye:
55 mm focal length
Now, here’s the exact same view, but taken with my lens set at 18 mm. Look how much more of the view you can see:
18 mm focal length
Fixed/Prime Lens vs Zoom Lens: A lens with just one focal length number in the description (for example, a 100 mm lens) is called a Prime Lens. This lens has one focal length option- that’s it. The only way to zoom with a prime lens is with your feet. A zoom lens, on the other hand, has a range. For example, a common lens is an 18-55 mm lens. This lens runs the range from 18 mm (wide angle) to 55 mm. With a zoom lens, (as the name indicates) you can zoom on the lens itself, without having to move.
Now let’s talk about sensor sizes again, and how they tie into lenses and focal length.
A Full Frame sensor will give you the accurate focal length on a lens, as we discussed above. However, if you are reading this post, chances are you don’t have a full frame sensor on your camera, and don’t anticipate one in the near future. You probably have/will be getting, a Cropped Sensor Camera. Here’s why this is important: the crop sensor on the camera affects the focal length of your lens. In the specs of the camera it will give you the Crop Factor. a 1.5x crop factor on a camera will multiply the focal length of the lens by 1.5. For example, a 50 mm lens will function as a 75 mm lens on such a cropped sensor camera. It is important to consider this when choosing a lens on a cropped sensor camera. (Note the crop factor information on the sensor size chart above.)
F-Stop and what it means: the F-stop number represents the size of the aperture, or opening which allows light into your picture. The number indicated in the lens specs is the lowest possible f-stop.
This is a bit counter-intuitive, so pay attention: the lower the f-stop, the larger the aperture, or opening, which means the more light you will have in your photo. If all you plan to shoot is outdoor photos in the middle of a sunny day, this number isn’t that important to you. But if you, like me, do lots of photography in low-light situations (such as your kitchen at midnight) the minimum f-stop number is very important. I mostly use a macro lens with a minimum f-stop number of f/2.8. That’s what I use for 95% of my nighttime food shots. Many people like to use a 50 mm f/1.8 (or f/1/4, if you can afford it) as those are very low, giving you the largest possible aperture, or opening for your picture.
Macro Lenses are important for people interested in food photography, as close up photos of food are often the ones we most want to sink our teeth into. One important specification to look at is the maximum reproduction ratio. A ratio of 1:1 means that you can take a photo in which you reproduce the subject it’s actual size. A ratio of 1:2 will let you reproduce the subject half it’s size. If you are wondering why a macro lens is important, this is it. A reproduction ratio of 1:5.5 won’t cut it with food photography.
Once you chose your camera and your lens, you will need to learn about other terms, like shutter speed, ISO, aperture, among others. If you don’t have a DSLR camera yet, and these numbers and terms all seem very difficult to understand, don’t panic. Once you hold the camera in your hand these numbers will make a lot more sense to you.
My biggest piece of advice for the new camera owner is this: immediately take it out of auto mode to force yourself to learn the settings. The best guide I’ve seen for this is at Kevin and Amanda.
If you just got your camera and you’re panicking because you are in over your head and totally lost, calm down. I was there too. I got through it. You will too.
Some general tips before purchasing a DSLR camera:
- Don’t overspend on the body. In most cases, it pays to go with a less expensive model and spend the extra money on the lens.
- Don’t be sucked into consumer tricks like “packages” which contain a whole bunch of accessories that you don’t necessarily need or want. Focus on the body and the lens(es) and worry about the accessories later.
- When choosing between Canon and Nikon (or any of the other camera companies) choose carefully! Lenses can’t be switched between companies, so once you buy a Canon or Nikon lens, you basically sign yourself up for life. Think of it as getting married to one of these camera companies.
- Don’t necessarily ditch the kit lens. The popular advice online is not to buy the kit lens, but I don’t think it’s so simple. If you plan to do nothing but food photography with your DSLR camera, you will probably never use the kit lens. However, if you have a life outside of food blogging (I see your eyes rolling here) there will be times that you will want a zoom lens with a wider angle, and will really be happy to have the kit lens. I can’t tell you how many times I have been thrilled to have my 18-55 lens. It is important to note that if you change your mind later on, you will never be able to get the kit lens as cheaply as you can together with the body.
- As a salesperson, I am probably supposed to push extended warranties, but I am not gaining anything by telling you this: I am a huge fan of them. I bought one with mine, and think you should to. Drop your camera a month after you buy it and your manufacturer’s warranty won’t cover it.