Yes, the image sensor on the X-T3 in the photo has been enlarged by nearly 50% as referenced by the X-T2 in the photo. There’s a reason for this.
At the risk of sounding like a fanboy, I’d like to present this possibility. Fujifilm proudly declared they would not be going with a 35mm sensor size in the future, for one, believing that it’s a bit redundant since they currently cover APS-C and cropped medium format. There are significant benefits to both formats: the former covers a Super35 area and is currently fast enough for excellent video capabilities that consumer level 35mm cameras are currently unable to match, while medium format has a level of detail and low light capability that exceeds all current 35mm sensors. However, as tech progresses, 35mm sized sensors will eventually obtain today’s level of capability in both sensor sizes. APS-C will eventually hit a point where it cannot go any further due to simple physics and while that point can be delayed through technological advancement, those very same technologies will only increase the efficiency of 35mm sensors. APS-C will need to increase in size for more headroom.
At the risk of becoming long winded, Fujifilm is one of very, very few to have made such an investment into APS-C. Their lenses are all designed for that sensor format without any flexibility to adapt to a 35mm sized sensor in the future, unlike Sony and Leica have in more recent history. The imaging circle of their lenses is so tight, they had even once declared that in-body image stabilization wasn’t possible. With the advent of the X-H1 however, we know that wasn’t completely true. But, because of that very camera, I have to ask this question: could their lenses cover an APS-H sized sensor without significant vignetting? The total imaging circle covered by the X-H1’s sensor has to be larger than the APS-C sensor itself due to its movement as required for IBIS operation, so would it be enough to accommodate an APS-H sized sensor?
An APS-H sensor is 5.1 x 3.3mm larger in height and width, respectively, over an APS-C sensor That results in a nearly 50% increase in surface area. 50% more light or 50% more resolution or even 25% more of each over current sensors. The benefit is a sensor with characteristics closer to that of 35mm, giving Fujifilm more headroom, yet hopefully without the problem of having to reinvent their lens lineup.
The X-T2 is an excellent camera and my X-T3 is a clear step ahead in capability, but I can’t help but ask, “what’s next?” Micro 4/3 seems to have hit its resolution to sensitivity limit, unable to increase the resolution without significantly crippling sensitivity. It’s a problem Panasonic seems willing to resolve by shifting their focus away from that format and towards 35mm.
People generally don’t care what size their image sensor is as long as it gives them the results they want. APS-C was once the ideal balance between price to performance for consumers but is slowly being supplanted by 35mm in the consumer space. The issue is unique to Fujifilm in how they’ve chosen to build their X-Series lineup around a singular sensor size with no headroom for a larger format. While they’re to be commended for eliminating as many variables as possible to create the highest quality lenses, the result paints them into a corner. Granted, they could release a 35mm body that utilizes their GFX format lenses and mount, but the jump in size and cost would chase away a significant portion of their customer base.
By going with APS-H, if possible, they could gain tangible benefits now and headroom for later, for far less cost, and do so without alienating their largest group of users who happen to also be the most price sensitive. Their current and future lens purchases would be safe investments. The only real loss would be the inability to offer IBIS in any APS-H equipped X-Series body.