Is the Fujifilm X-T3 Full-Frame & Does It Matter?

Full-frame versus cropped sensor is a long-standing debate in the photography community. When it comes to the Fujifilm X-T3 this debate brings up the question: is the Fujifilm X-T3 full-frame and does it matter?

The Fujifilm X-T3 uses Fuji’s 26.1 Megapixel X-Trans CMOS 4 sensor. The X-T3 uses an APS-C sensor which has a 1.52x crop factor when compared to a standard full-frame camera.

Keep reading as I break down the benefits and limitations of using a larger sensor and to using Fujifilm’s X-T3.

Sensor Sizes Explained

Sensor	Measurements (W, H, D)	Crop Factor
35mm Full Frame	35.8mm x 23.8mm x 43mm	1.0
APS-H	27mm x 18mm x 32.5mm	1.32
APS-C	23.5mm x 15.7mm x 28.3mm	1.52
APS-C (Canon)	22.2mm x 14.8mm x 26.7mm	1.61
Micro Four Thirds	17.3mm x 13mm x 21.6mm	2.00
Medium Format	43.8mm × 32.9mm x 54.8mm	0.78

The job of the camera sensor is to recognize light and convert it into a signal (data) using light-sensitive cavities called photosites. These photosites are the physical representation of pixels, which are digital light and colour-sensitive blocks that form an image.

Lenses and images work together to function similarly to how your eyes do. Light hits them and is converted to information and sent to be interpreted by your brain; your camera’s image processor is its brain.

The flaw to the analogy of sensors being equated to your eyes is that your camera’s sensor isn’t made up of just one eye, it’s made up of a bunch of eyes, photosites, that capture light and convert them into signal to be processed.

It is important to note that the exact measurements of a sensor may vary between camera brands. A larger sensor captures more light, can create a shallower depth of field, and have a better dynamic range. Sensor size is important and plays a role in how your camera captures light but is not the same as your sensor’s resolution.

What Size Is the Fujifilm X-T3 Sensor?

The Fujifilm X-T3 features a 26.1 Megapixel X-Trans CMOS 4 sensor with a primary colour filter. This is an APS-C sensor which means it has a crop factor of 1.52x.

CMOS sensors have active circuitry that typically takes up real estate on the surface of the sensor which makes this area a dead zone. The way Fujifilm fixes this problem is by back-illuminating the X-Trans CMOS 4 sensor.

CMOS, which stands for complementary metal-oxide-semiconductor, is a type of active-pixel sensor (APS). This is not to be confused with the APS in APS-C, which stands for advanced photo system type-c.

One key advantage to CMOS sensors is that they are less prone to blooming, an issue that arises when one overexposed pixel bleeds into surrounding pixels.

Sensor Size vs Number of Effective Pixels

Sensor size and a sensor’s number of effective pixels have a cause-and-effect relationship, changing one without the other will have an effect on your images.

To understand the number of effective pixels we first need to know the difference between effective and actual pixels. Effective pixels are pixels that are actually used as part of your image. Active pixels are used to determine the edge of your sensor or to transmit colour data. The number of effective pixels, as the name suggests, is the number of pixels that make up your image files.

Increasing the size of your sensor without increasing the number of effective pixels means your need larger pixels (technically called photosites) to fill out your sensor. The benefit to this, among others, is that each pixel will have better low-light performance, and will reduce noise.

If you increase the number of effective pixels without increasing your sensor size, you will need to make your pixels (again, technically called photosites) smaller. Smaller photosites will capture less light, decreasing low-light performance and increasing noise.

When a pixel captures less light, its signal-to-noise ratio increases. I have an entire article breaking down exactly what noise and signal-to-noise ratio are.

How Are Sensor Size and Lenses Related?

To understand how sensor size and lenses are related, we need to first understand what the crop factor is.

The crop factor is the diagonal size of the sensor using the standard 35mm full-frame as a reference point. Since it is the reference point, a standard full-frame camera has a crop factor of 1.0 meaning it has no crop.

What does this mean? The Fujifilm X-T3, since it is an APS-C sensor, will take images that appear 1.52x cropped in. For example, if you take a photo using the Fujifilm XF 56mm 1.2 R WR the field of view will appear as that of an 85mm lens.

Though the field of view is where the similarities stop when dealing with lenses on cropped sensors. What I mean is this: a 56mm lens will always be a 56mm lens regardless of the sensor. The lens compression, lens distortion, aperture, and other features of your lens will not be affected by a change in sensor size. So if you think you will be able to get the same bokeh on the X-T3 using a 56mm lens as you would get using an 85mm lens on a full-frame camera, sorry, but that is not the case.

This is the reason why you may hear a 56mm lens referred to as an “85mm equivalent” when used on an APS-C-sized sensor, that 56mm lens has the same field of view as an 85mm on a full-frame camera.

Does Sensor Size Matter?

If you were to search forums and online discussions debating whether or not sensor size matters, you’ll find a lot of answers that say “it depends” or “yes and no”. In the end, yes, sensor size matters. When deciding on a camera, sensor size should play a role in your decision-making.

Now, I can’t say which sensor size is the “best”, because that is entirely subjective, but I can list some of the factors involved with choosing which sensor size for your next camera.

In general, DSLRs and mirrorless cameras will have sensors between 12 Megapixels to roughly 50 Megapixels (with exceptions of course). This means a larger sensor will have better low-light performance.

This is usually the main factor for photographers when choosing a new camera, but some other factors that may be considered are; lens selection, field of view, and depth of field.