I’ll be honest with you. I spend most of my life in Photoshop, not behind a camera. But lately I’ve been pulling more raw files from photographers who are shooting on higher-end Fujifilm systems, and when a client sent me a batch of images from a GFX100RF, I realized I had no idea what I was even looking at in terms of the files, the crop options, or why some shots had wildly different aspect ratios baked into the metadata. Understanding the camera that captured an image matters, especially when you’re the one doing the post-processing work.

So I went looking for a solid explainer and landed on this series from John Greengo, who is genuinely one of the clearest camera educators working right now. Section 2 of his Fujifilm GFX100RF course is specifically about camera basics, and it’s the kind of foundational breakdown that saves you from a lot of confused squinting later.

Why the GFX100RF Doesn’t Fit Neatly Into Any Box

The first thing Greengo does is tackle what kind of camera this actually is, because it’s genuinely unusual. The GFX100RF sits in a category he describes as a “large sensor compact” – and that label is doing a lot of work. This is a medium format camera. Not full frame. Not crop sensor. Medium format, meaning the sensor is physically larger than what you’d find in a Canon R5 or Sony A7 body.

But it’s also small. Like, coat-pocket small by medium format standards. That combination is rare enough that a lot of shooters don’t quite know how to position it in their heads. Is it a serious studio tool? Is it a street camera? Greengo’s answer is essentially: both, and that tension is the whole point of the product.

How the Camera Actually Operates (No, There’s No Autofocus Joystick)

Here’s where it gets genuinely useful for anyone working with files from this camera. The GFX100RF has a fixed lens – a 35mm equivalent focal length of roughly 32mm in the medium format world, which translates to a field of view similar to a 25mm on full frame. There’s no swapping it out. No zoom ring. What you see is what you get.

Greengo walks through how Fujifilm compensates for this with something that functions like a “digital tele-converter” – essentially using the 102 megapixel sensor’s resolution headroom to let shooters crop in-camera at 35mm, 50mm, and 63mm equivalent fields of view, all while keeping files large enough to still be usable. The 102 megapixel count isn’t just a spec flex. It’s functional architecture for a camera that will never have a zoom lens.

This matters enormously in post. When you receive files from this camera, some of them may already be cropped. The aspect ratio may not be the native sensor ratio. Greengo covers the primary controls layout, including how exposure compensation, shutter speed, and aperture are handled through physical dials on the top of the body rather than menu-driven controls. Old school in the best way. If you’re retouching images and wondering why a client’s shots have strong vignetting or particular rendering characteristics, knowing that this is a fixed prime at f/4 or wider explains a lot.

The Sensor and What 102 Megapixels Means for Post Work

The image sensor section of this tutorial is the part I’d actually replay a few times if you’re a post-production person. The GFX100RF uses a 102 megapixel medium format BSI CMOS sensor with a native aspect ratio of 4:3. Files are enormous. We’re talking tiff exports that will genuinely slow Photoshop down on an underpowered machine.

The practical implication Greengo points out is that medium format sensors have shallower depth of field relative to their focal length compared to smaller sensors – which affects how you handle masking, subject separation, and any frequency separation retouching. The blur falloff behaves differently than you might expect from full frame files. If you’ve ever had a composite look slightly “off” because the background blur characteristics didn’t match your subject’s source image, sensor format differences are often the culprit.

Where I’d Push Back Slightly

Greengo keeps things very camera-operator focused in this section, which makes total sense for his audience. But from a post-processing angle, I’d have loved more discussion about the color science baked into these files – specifically how Fujifilm’s Film Simulations interact with the raw data and what that means if you’re handing files off to a retoucher who isn’t aware they’ve been shot in Eterna or Velvia mode.

I’ve had this exact problem. A photographer sent me a batch that had Classic Chrome simulation applied and then exported as JPEGs assuming I’d just “fix the color.” There wasn’t much to fix. It was baked in. Understanding the camera’s processing pipeline from the shooter’s end would have prevented that conversation entirely. That’s not a criticism of this tutorial. It’s a gap I’d fill with a companion piece about Fujifilm color profiles in Lightroom and Camera Raw.

The Practical Upshot for Anyone Touching These Files

The most valuable thing this tutorial does is reframe the GFX100RF as a deliberate design choice rather than a compromise. The fixed lens is not a budget decision. The in-camera crop system is not a workaround. These are features built around a specific shooting philosophy, and understanding that changes how you approach the files downstream.

If someone hands you GFX100RF images to retouch or composite, treat them with the same care you’d give medium format work from a Hasselblad or a Fujifilm GFX100S. The resolution gives you room to work, but the files are hungry for memory and the color rendition rewards careful handling.

Watch the full John Greengo series for the visual walkthrough – he covers every physical control and menu structure in a way that’s genuinely hard to replicate in text. Start with section 2 here and follow the series links in the description for the complete course.