“I want a new camera, but what should I get?” – Appetizer 4: The Mirrorless Interchangeable Lens Camera

All in the Name

Mirrorless Interchangeable Lens Cameras (MILC) are sort of a hybrid Digital Single Lens Reflex and Point & Shoot. As the name implies, they lack the reflex mirror of a DSLR (see Appetizer 3 for an explanation about reflex mirrors); however the lenses can be interchanged.

You may have also heard some of these cameras referred to as “four thirds”, which refers in part to the aspect ratio of the image sensor (i.e. 4 units wide to 3 units high* – the same ratio as an analog television set) of the first models on the market from Olympus. The “Four Thirds system” is actually a standard created by Olympus and Kodak for their DSLR design** (you can read about the standard in all its technical glory here), while the mirrorless camera falls under a standard called “micro four thirds” (again more fun technical stuff). Olympus and Panasonic MILCs have 4:3 aspect ratio image sensors, while other brands’ sensors vary in size an aspect ratio.

Presently, most MILC model names contain some form of abbreviation that is indicative of their lens mounting system (refer to the “Some Examples of MILCs by Brand” section below.)

* The aspect ratio for almost all DSLRs is 3:2 (except those made by Olympus and Pentax’s flagship) – the same portion as for 35mm film; a 6″ X 4″/15cm X 10cm photograph is 3:2
** Kodak has not had a DSLR on the market since around 2004

General Characteristics

  • Many MILC cameras have small, thin bodies described as “rangefinder-like”* while others have thicker bodies with a prominent grip on the right side like some superzooms, they can look like a DSLR with the top cut off
  • Weight starts around 8oz./227g for the body with batteries and goes up depending on body style and weight of added lens
  • The removable lens does not retract flush to the body, and all lenses are barrel-shaped with a circular “window” on the end to let in light
  • Many MILC lens mounts are not interchangeable with a camera company’s DSLR lenses (with the exception of Pentax’s K-Mount camera); although many brands have created adapters to work with the two camera types**
  • Lenses can be fitted with filters (look for ∅ on the end with a number in millimeters, which will tell you the diameter of filter that will fit it)
  • Some models have a built-in pop-up flash that lies flush with the body, while others have a hot shoe for mounting an external flash – check the specifications of a particular model to if you are looking for one feature over the other
  • Powered by Lithium Ion Batteries
  • Can shoot video; many shoot in High Definition
  • Can photograph both RAW (unprocessed) and JPEG files (see definitions below)
  • Do NOT have an optical viewfinder

Note: Presently, you cannot shoot in “Bulb” mode (keep shutter open as long as you want) with MILCs.

* This type of camera was fitted with a mechanism that aided the photographer finding the distance to the desired subject and focus it sharply; think of the rectangular black and silver cameras of the 1950s-70s; the top-end brand, Leica, epitomizes the rangefinder
** To date, none have created a “backwards compatible” adapter whereby MILC lenses can be fitted to DSLRs

Pros and Cons


  • Smaller and easier to handle/operate than a DSLR; less equipment to lug around
  • Image sensors produce high-quality images, like those in the DSLR
  • With interchangeable lenses and many similar mode settings to the DSLR (including manual), the MILC gives you more creative latitude than even the most advanced Point & Shoot
  • Depending on the brand and lens mount, you may be able to use DSLR lenses


  • If you are inclined towards a DSLR, the MILC is not yet a lighter replacement, especially if you want features like “bulb” exposure
  • If you plan to purchase more lenses and are looking to keep the system lightweight and portable, you need to spend some time comparing options by brand, or else you could end up with a camera that is as heavy as a DSLR
  • There is no optical viewfinder; therefore you are always using the rear LCD on the camera
  • Presently, the cost of the MILC system is as much as for entry-level DSLR

Some Examples of MILCs by Brand

  • Canon EOS M (EOS = Electro-Optical System autofocus, M = EF-M lens mounting system; can be accessorized with an adapter for some Canon DSLR lenses)
  • Fuji XE/XF (named for their X-mount lens system)
  • Nikon 1 (J1, J2, V1, V2; 1-Mount, can be accessorized with an F-mount adapter for their DSLR lenses)
  • Olympus PEN “Micro Four Thirds” – can be adapted to fit any Micro Four Thirds system lens
  • Panasonic DMC-G “Micro Four Thirds” – can be adapted to fit any Micro Four Thirds system lens
  • Pentax K (compatible with all K-Mount lenses) and Pentax Q (Q-Mount, can be accessorized with a K-Mount adapter)
  • Samsung NX (NX Mount lenses)
  • Sony α (Alpha) NEX (Sony E-Mount system; some compatible lenses are manufactured by other brands, such as Carl Zeiss)

RAW and JPEG Format Definitions

RAW: Unprocessed image files (dubbed “RAW”, although there is no such thing as a .raw file). Think of them as digital “negatives”, as they contain all the information about the picture you took, have the most options for editing, but are cannot be shared or made into prints until they are processed. These files also take up considerable space on your camera’s memory card (e.g. 20 MB or more). In order to edit them, you will usually have to use the brand software that came with your camera (every brand has a different file type for RAW) or advanced editing software, such as Adobe Photo Shop.

JPEG: A standardized file format (.jpg) created by the Joint Photographic Experts Group that can be viewed on any website and is also recognized by home and commercial printers. When you take a picture in JPEG mode, the camera automatically removes all extraneous data from the image file – which you do not even notice is gone – and compresses into a manageable file size (e.g. 2MB to 6MB). The picture is then ready for sharing, editing, printing, etc. immediately. You can further edit and compress the file as you like; however, since the file has already had much of its data removed (known as “lossy compression”), you are limited in how much you enhance the image and any compression on an already compressed image will eventually degrade it to a series of blotchy squares.

Helpful Websites

www.dpreview.com: Digital Photography Review, owned by Amazon.com. Comprehensive reviews, and you can compare up to 20 cameras – including obsolete models – side by side at once. This feature is found under the “Cameras” Tab.

www.futureshop.ca: This is the website for Future Shop. It can be useful as a reference, because you can look up the specifications on current products, and terms in red text are hyperlinked to user-friendly definitions. Go to departments >> cameras >> pick your category of camera, click on a model, and then go to the tab labelled “Details & Specs”.

This content is published under the Attribution-Noncommercial-Share Alike 3.0 Unported license.

Catherine Glynn

Years ago, I had a great camera given to me as a wedding present from my husband. My favourite camera of all time was the Polaroid Land Camera that instantly produced the pictures. The unfortunate aspect about the pictures was they were roughly 70 cents to a dollar for a single picture. Over time, they also faded.

My son was just talking about wanting to get a good camera. I will show him this article.

I have to admit, I rarely take a picture anymore. My biggest problem is taking the time to download the pictures. Mostly, laziness, I must admit.

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