Mirrorless and DSLRs – Tech Fundamentals Course

After last week’s chat about smartphones and compacts, let’s move on to the more serious camera types – Mirrorless and DSLRs. These are cameras which are bigger, generally more expensive, but also offer you more control, more options to expand, and with careful use, the best image quality.

Mirrorless Cameras

Mirrorless cameras are relatively new – they’ve really only come into their own in the past decade or so.  In the early days they weren’t considered a viable option for professionals, but these days there are some very capable mirrorless systems out there, and you may prefer the way they work to using a DSLR.

A mirrorless camera - a Nikon Z7 - in action
A mirrorless camera – a Nikon Z7 – in action

Mirrorless cameras will have interchangeable lenses, and should offer you the full range of exposure modes and file formats.  They work fairly simply. The lens projects onto a sensor within the camera and that data is then projected onto a screen at the back, or to some sort of electronic viewfinder. Usually you take pictures by pressing a shutter release button, but increasing numbers of cameras offer some sort of touch screen functionality on the back.  This opens the shutter in front of the sensor for the set length of time for the shutter speed. The image is then recorded to a memory card

Not all mirrorless cameras come with an EVF (electronic viewfinder), but most now do, and pretty much all of them allow you to angle the rear screen in some way as well.  They used to be very slow at autofocusing, but in recent years (I’m writing this at the end of 2019) this has changed dramatically, and some mirrorless cameras now focus faster and better than DSLRs.


  • Smaller and lighter than DSLRs, as they have no mirror box and prism to incorporate
  • Many models can be expanded with a system – interchangeable lenses, flashes, grips, all sorts of extra toys can be bought to expand the range of what you can shoot
  • They are capable of shooting totally silently.  This may not be something you’ve ever thought about, but can be really useful in some situations – wildlife and wedding photography would be two I can think of
  • The EVF or screen can be really helpful in low light – you may find it much easier to see what you’re doing and compose shots than you would with a DSLR
  • The amount of information available on either the rear screen LCD or the EVF is very useful.  Inside the viewfinder of a DSLR you may have some exposure information, and perhaps a flash ready light or number of remaining frames.  In a mirrorless display you can have a huge amount of extra info such as artificial horizons, live histograms, and a wealth of info about the camera’s current settings and status.
  • If you shoot video, mirrorless cameras are often easier to use than DSLRs.  There are often lots of feature differences, but mostly they’re easier because it’s possible to shoot using the EVF, rather than always having to use the rear screen.  For hand held shooting, particularly with a shoulder rig of some sort, this a big plus.
  • The rear screen may flip in various ways, allowing you to shoot comfortably in different positions such as very low or high, and it allows you to shoot with your head away from the camera, which can suit some portrait subjects well.


  • Whilst the displays and screens offer more information, you are always looking at a screen, rather than the real thing, and this can sometimes cause problems.  For one thing, there will always be a slight delay between what happens in front of the camera and what appears on screen, and this can be challenging if you’re shooting high-speed action.
  • In a similar way, some mirrorless cameras can be slower to start up from “off” than a DSLR.  If you’re shooting lots of action, you’ll want to bear this in mind.
  • They tend to have slightly worse battery life than a DSLR, mostly because of how much more you need to use the various screens, but this is improving.


A DSLR camera
A DSLR camera

How DSLRs work.

DSLRs probably function in the most complex way of the types we’ve examined. You have an interchangeable lens on front of camera, this lens focuses light onto an angled mirror inside the camera body. This bounces the light up through a prism into a viewfinder, where you can compose the image. When the shutter is pressed, the mirror raises, and light passes through to a digital sensor in the back of the camera. Most DSLRs can also do “live view” where image can be viewed and shot directly from the rear LCD screen. Once taken, images are then recorded to a memory card or cards inside the camera.

DSLR pros and cons.


  • You have full control over the image, and are able to choose exposure, file format, lens focal length, and pretty much any setting you wish.
  • They’re very quick to respond and focus – it will shoot when you tell it to (or can be programmed to),
  • They have much larger sensors (though not all are “full frame”) this means good shallow depth of field if that’s what you want, and good low light performance.
  • They’re very expandable – there’s a huge range of lenses, flashes, accessories and so on – right through to esoteric things like waterproof housings, remote releases, you name it!


  • Big, bulky and expensive. As I’ve already said, a camera is no use if it stays at home, or in the boot of the car.

So, there you have it, a simple run through of mirrorless and DSLR cameras. If you’re serious about your photography, you’ll want to invest in one of these camera types before too long, as they offer the most control, the most expandability, and carefully used, the best image quality. At this stage (early 2020) I’d be hard pressed to choose between them. Speaking honestly as a professional, I use my mirrorless Nikon Z6 for video work, as it’s really well suited to it, and my DSLR Nikon D850 for stills, as it’s still got the edge (for what I shoot) in stills.

I’d strongly suggest that if you’ve not bought anything yet, you go to an actual real world camera shop, and get your hands on some different ones. You may well find that mirrorless if much more your cup of tea, with it’s incredibly clever displays, smaller size and weight. Or you might prefer the style and working method of a DSLR. What you prefer matters far more at this stage than my opinion!

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