The DSLR Photographer DSLR Reviews – Guides – Tips

How DSLR Cameras Work


Digital Single Lens Reflex, shortly DSLR, stands for:

  • Digital – No more film, everything is digital
  • Single Lens – Ability to change lenses
  • Reflex – The light is reflected inside of the body

Now let’s take a look at the important parts that help you at taking the images.

How Your Photograph is Created

Part 1 – Before Taking A Picture


DSLR cameras have hundreds of parts inside but let’s focus on the most important ones:

  • Mirror -Position at a 45-degree angle, it reflects the light into the pentaprism/pentamirror
  • Pentaprism – Thanks to its shape, the light is properly reflected into the viewfinder
  • Shutter – Covers the sensor until you press on the shutter button
  • Sensor/Film – CMOS or CCD chip that convers the light into images
  • Auto focus Chip – There are also devices for auto focusing and metering the proper exposure

Basically all of these objects are created to give as much light as possible into the viewfinder, without losing any quality. The animations are really simple, but it displays how the light reflecting actually is like.

Part 2 – Getting Ready

  • Now we know that the light is constantly going through the lens and hitting the mirror
  • From then most of the it goes into the pentaprism and then the viewfinder, when taking a picture, some of it is used for exposure calculations

This is happening all the time in your cameras, the only way to stop it is to put on a lens cap.

More professional cameras use a pentaprism, just like in the film days. To make the cameras cheaper though, lots of beginner models use pentaprisms that are somewhat close, but not as bright!

Let’s take a look at what your camera does when you are ready to take a picture.

Part 3 – Creating the Image


  • You press on the shutter button
  • The mirror flips upwards and reflects the light further up, which blocks the light going to your viewfinder
  • The aperture narrows (unless you have it at its largest setting)
  • The shutter opens and all of that light hits the sensor; what we call an exposure
  • Once the exposure is over the shutter goes back and the mirror flips down
  • You can now see your image on the LCD screen

And that’s pretty much it! All of the things I wrote above happen in such a short time you can’t even tell that there are so many things going on. Plus, the animation above is for 1 single photograph. Imagine how insanely fast this would look in cameras with 5 or more frames per second (Canon EOS 70D is a great example)

DSLR Cameras – Pros

  • Changing lenses – On a P&S camera, you are limited to the lens you have. DSLRs on the other hand, offer a ton of different lenses with all sorts of crazy focal lengths.
  • Bigger sensor – Their sensors are much bigger, which results in crispier images with less noise. They can also add more megapixels without sacrificing
  • Viewfinder – You’re actually looking through your viewfinder at the speed of light (thanks to the mirror)
  • Faster – Focusing, controls, menus, zooming, taking pictures; everything is faster
  • Picture quality – Because of better sensors, the contrast, colors, dynamic range, all of that is much better

DSLR Cameras – Cons

  • Size – You can’t put your DSLR in a pocket, or carry it around like a phone. It’s not a con once you get used to it, plus there are a lot of small DSLR cameras on the market today (Canon EOS 100D currently the smallest)
  • Price – New cameras started at $400, used ones at around $200. Combine that with tripods, memory cards, hard disks and your wallet will suddenly be empty.

All DSLRs have great quality, it’s up to you how seriously you want to take photography and improve.

Next: Sensor Size & Crop Factor Explained