MFT was co-developed by Olympus and Panasonic in 2008. The pair wanted a compact alternative to full-frame DSLRs that still offered excellent image quality and the versatility of interchangeable lenses. The result was a system with a smaller sensor that didn't require a mirror box or pentaprism to operate. That enabled companies to build smaller, lighter camera bodies and a vast library of pocket-size lenses. Before long, MFT was known as the perfect compromise for people who wanted to shoot beautiful images without the bulk and hassle of a full-frame DSLR kit.

In the years that followed, a bevy of rival systems popped up, including the Samsung NX line, which used a slightly larger APS-C sensor, and the Nikon 1 series, which sported a smaller CX format. Most of these struggled to gain traction, though a few, such as Sony's NEX and Fujifilm's X Series -- which both use APS-C sensors -- built a loyal following on a similar blend of portability, image quality and nostalgic design.

Leica launched a full-frame rangefinder in 2009; however, the onslaught of full-frame mirrorless cameras truly started in 2013 with the Sony A7 and A7R cameras. They were expensive -- at launch the A7R cost $2,300 for the body alone -- but produced excellent images and proved definitively that a larger sensor could be squeezed into a smaller package. Fast-forward roughly six years and Sony's latest models, the A7 III and A7R III, are incredibly popular with photographers, filmmakers and YouTube vloggers alike. The camera industry's lumbering giants, Canon and Nikon, have just caught up and started releasing their own full-frame mirrorless cameras. Even Panasonic, a co-pioneer of the MFT system, has unveiled a Sony rival in the S1 and S1R.

Panasonic, Olympus' longtime MFT partner, has just released its first full-frame mirrorless.

Compact-camera sales have been obliterated by the increasingly competent photo- and video-shooting capabilities of smartphones. Doomsayers believe that a growing number of people are happy with their phone and will choose a full-frame system for enthusiast and pro-level photography. The hardware can be expensive, they argue, but the price will fall to a point where it's attractive to people who currently have the budget for an MFT system. "You can make a full-frame camera and it doesn't have to be super expensive," Northrup said in his YouTube video. Canon, for instance, has announced a smaller version of its full-frame EOS R camera ($2,299), the EOS RP ($1,299).

For now, though, MFT hardware is generally cheaper than full-frame mirrorless cameras. If you have a budget of $2,000, for instance, you can snag a more "complete" kit with a midrange body, some memory cards and a few entry-level lenses.

It doesn't always make sense, too, for photographers to continuously sell and upgrade their equipment. "Camera companies are always leapfrogging each other," explained Ellis, a wedding photographer based in Dallas, Texas. "And you need to look at the context of what was available at the time you made the purchase. Just because a new Sony [full-frame] camera has the same things the Olympus has... it doesn't mean that any photographer who's not loaded is just going to jump brands over one model."

MFT users also question the desirability of full-frame mirrorless systems. High-resolution images contain more detail and translate well to large, physical formats such as billboard ads. Most photographers, however, rarely require this many pixels. "Most photographers are thinking of the means and then forgetting the end," David Thorpe, a 74-year-old photographer and YouTuber, said. "What is the purpose of having 40 million pixels if your means of reproduction is 2,000 across? What are you going to do with all those pixels? What you're going to do is throw them away."

"What is the purpose of having 40 million pixels if your means of reproduction is 2,000 across?"

Thorpe has worked for magazines, newspapers and rockstar musicians including Sir Paul McCartney since he was 17. He argues that MFT is "way above the requirements" for most web and print publications. If you're shooting with a bigger sensor, it simply takes longer to export, resize and send the files. "What they want is fewer pixels, better quality," he said. MFT is also fine for wedding photography, according to Ellis. He regularly produces images that are 20 or 30 inches across with his Olympus OM-D E-M1 Mark II ($1,599).

"And the only time it becomes an issue is if you have two identical pictures taken with different cameras and you're comparing them side by side in a sniff test," he said. "Anytime you make a larger print, the viewing distance of that print is critical. Nobody appreciates a 20-by-30-inch print from four inches away. You shouldn't. You should be back a couple of feet to take in the whole print. At that distance, the resolution becomes a very, very minor issue."

Full-frame mirrorless cameras carry hidden costs too. For one, bigger files require larger and faster memory cards. The stellar Nikon Z7, for instance, doesn't have an SD card slot: It only takes the capable and bank-breaking XQD memory cards. For another, you need a beefier PC and, depending on your preference, larger backup drives and higher-capacity cloud storage. For enthusiast and semi-pro photographers, these workflow and hardware changes add up. "Do you really need it? That's an important question, because if you're just spinning your wheels for all that stuff then that's certainly a big drain on your bank account," Ellis said.

Olympus recognizes that smartphones are replacing the entry-class camera. But the company is adamant that MFT is a logical choice for anyone who wants to step up and take their photography more seriously. "If you compare the size of full-frame mirrorless cameras and lenses to mobile phones, it's a huge step," Akihiko Murata, VP of Sales and Marketing at Olympus, said. "So in this place, [Olympus] can play a big role. MFT can play a big role."