Every Design Decision on the Fujifilm GFX100RF Was Made to Keep It Compact
Everything about the Fujifilm GFX100RF has been designed in service of the overarching goal of making it as small and lightweight as possible. That doesn’t mean Fujifilm didn’t try adding a faster lens and in-body image stabilization to early designs, however.
The size and weight of the GFX100RF is likely taken for granted. Given the size of the sensor, it’s incredible how the entire system is only just slightly larger than the APS-C X100VI. Speaking to PetaPixel at Fujikina in Prague in March, the company says it designed the camera to be compact first and foremost from the very beginning.
The design of the GFX100RF allowed Fujifilm to push the optics right up next to the sensor — far closer than they could if it was an interchangeable lens design. As a result, physics prevents them from recreating that form factor for use on the rest of the GFX system.
‘When we have an IBIS unit, the image circle has to be even larger… That forces the rear element to get bigger, which forces the camera to get bigger. It would have felt ungainly. Well, it would’ve changed the camera completely.’
“Because our first priority was how to make it smaller and lighter weight. So if we think about that kind of specification, eliminating the focal plane shutter is a really good thing for us to make it smaller. Because of the fixed lens, we can make it mount-free, allowing us to not care about the distance of the sensor on the lens — we can make it very close,” Makoto Oishi, Product Planning Manager at Fujifilm, explains.
There are notable engineering advantages to a fixed lens system when trying to achieve the smallest possible camera system size and weight. When developing the GFX100RF, Fujifilm looked at all of its existing optics and their features and considered them carefully before deciding on the eventual 35mm f/4 lens.
“We tried,” Oishi says. “We tried so many simulations not only for focal length but also the F numbers as well and even OIS. This is the best balance for us to achieve this size and weight.”
Once Fujifilm was able to eliminate the focal plane shutter and fix the lens, it was able to do quite a bit. The company says it chose a wide-angle lens for the GFX100RF because it wanted to leverage the resolution of the 100-megapixel sensor for those who wanted more zoom.
There are three major “pain points” that photographers have immediately pointed out about the GFX100RF: no hybrid or optical viewfinder, the speed of the f/4 lens, and the lack of in-body image stabilization. It’s important to address all of these points and explain Fujifilm’s decisions.
Design Choice: No Hybrid OVF
One of the defining design features of the X100 series is its hybrid optical viewfinder (OVF). It might, therefore, be strange to not see it on the GFX100RF. Fujifilm elected not to include it in this design because of its impact on the size of the camera body.
“It’s because of the size impact. We, of course, discussed installing the hybrid viewfinder, and created mockups to check the size,” TJ Yoneda, GFX100RF Product Planning team lead, explains.
“Actually the hybrid viewfinder was much bigger. It affected the size and the one thing we have considered together with that is since we decided to install the digital teleconverter, the indication of that would be very small in the hybrid OVF. It would be, practically, useless. So from a practical point of view, we decided to use a high-resolution EVF instead of the hybrid OVF.”
TJ also made sure to note that because magnification is so important to the experience of the GFX100RF, Fujifilm wanted to make sure the EVF experience was a “beautiful” one.
Design Choice: Lens Speed
For many photographers, f/4 seems slow. Fujifilm says that when it combines the size and performance of its sensor, f/4 is less of a compromise than it sounds on paper.
“So actually even at f/4, it’s almost a two-stop difference when compared to full frame. GFX offers super high resolution and the lens allows for super sharp subjects. So I think a really important thing is the separation of subject and background. As a large format camera, the separation is good enough with f/4, I think.”
It’s unusual for a medium format wide-angle lens to get much faster than f/4, and even more uncommon to see wide angle, fast aperture, and compact design.
Design Choice: No Stabilization
Some photographers might ask why Fujifilm decided to keep an ND filter in the lens as opposed to replacing that feature with optical image stabilization.
“We actually used the same shutter unit as the one in the X100 series,” Oishi explains.
“And originally X100 already had an ND filter inside, in the shutter. So that is why we can implement the ND in the GFX100RF. It is not simple to just take away that ND and put OIS in there because it has to move. It would require a different structure.”
‘We tried so many simulations not only for focal length but also the F numbers as well and even OIS.’
The inclusion of in-body image stabilization (IBIS) in the X100VI and the miniaturization of the motor for that explicit purpose has led many photographers to believe implementing a similar feature in the GFX100RF would be simple. Fujifilm explains it is more complicated than that.
When designing the GFX100RF, it originally designed multiple mockups, one of which included IBIS. However, there was a problem.
“It was really big. Really big,” Oishi explains. Using his hands, he gestured the size and it appeared almost double, if not more, in scale compared to the final GFX100RF. It wasn’t just thicker, it was also taller — and substantially so.
When making the IBIS unit for the X100VI, it only ended up adding three millimeters to the design. However, when scaling that up to the size of the medium format GFX sensor, everything ballooned with it. Adding an IBIS unit isn’t just adding that hardware, it also means providing enough coverage for a larger image circle with the lens, giving it the coverage it needs as the sensor shakes.
“When we have an IBIS unit, the image circle has to be even larger. The 30mm GF tilt-shift lens, for example, has an 85mm image circle. So it’s equivalent to designing a 19mm lens or something close to it. That forces the rear element to get bigger, which forces the camera to get bigger,” Justin Stailey, Senior Product Manager at Fujifilm, explains. Therefore, adding IBIS to the GFX100RF would have cascading effects.
“It would have felt ungainly. Well, it would’ve changed the camera completely.”
Image credits: Erin Thomson, PetaPixel
