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What is 35mm Format Mode in Fujifilm GFX Cameras?

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Fujifilm’s medium-format GFX cameras (link to B&H) – like the GFX50S II, GFX100S, and now the GFX100S II – have an option in the SHOOTING SETTING menu called 35mm Format Mode. At first glance, it seems that this just crops your photo and changes the aspect ratio. But there’s more to it than that.

What is 35mm Format Mode in Fujifilm GFX?

What 35mm Format Mode Does

35mm Format Mode “crops in” on the sensor. The entire sensor will not be used to record the image. Rather, it uses a smaller image area in the center of the sensor.

Instead of the sensor outputting a 50 or 100MP image, the image is downsized to approximately 42MP (GFX50SII) or 60MP (GFX100S). This is not only true for the JPG output but also for the RAW files.

This smaller image area actually correlates to the size of a full-frame sensor, approximately 36mm in width, whereas the GFX sensor is 44mm wide.

fujifilm gfx vs full frame sensor size
Approximate size of a full-frame sensor compared to a Fujifilm GFX sensor.

In addition to downsizing the image, the aspect ratio also changes from the standard 4:3 GFX format to a 3:2 format.

You’ll see a “35” in the upper-left of the standard indicators display. The Image Size will be locked in at “L 3:2”. This smaller cropped area is reflected in the Live View.

35mm format mode indicator
35mm format mode size

When to Use 35mm Format Mode

Why or when would you use 35mm Format Mode?

Well, if you just want a smaller image, you don’t need the 50MP or 100MP offered by your camera, you can use this to get some really great high-resolution photos albeit slightly smaller.

But perhaps the more important reason for enabling 35mm Format Mode, a reason not mentioned (directly) in the manual, is for compatibility with lenses designed for 35mm cameras.

One of your favorite lenses might have been designed for either 35mm film cameras or full-frame digital cameras. You can use those lenses on a GFX camera with the appropriate mount adapter (link to B&H).

Those lenses, however, will project a smaller image area onto the sensor. Your resulting images will have some serious vignetting around the edges if 35mm Format Mode is OFF.

gfx sensor vignetting
The image area (inside the blue circle) projected onto the sensor from a full-frame lens will be smaller than the GFX sensor.

So, you enable 35mm Format Mode to crop that vignetting. You’d have to do it in post-processing anyway, right? This takes care of that step for you. Save digital storage space, save post-processing time, and get those in-camera JPEGs if that’s what you’re aiming for.

gfx vignetting without 35mm mode
This is a simulation of what your image would look like if 35mm Format Mode was OFF, but you were using a lens designed for full-frame cameras.
35mm format mode crop size
35mm Format Mode will crop the white area.
35mm format mode after crop
The resulting image – both RAW and JPEG – will be a smaller crop without the vignette caused by the smaller image area.

35mm Format Mode Options

These are your menu options:

  • ON (use if the camera doesn’t recognize your adapter)
  • OFF (this mode will never come on)
  • AUTO (the camera will automatically switch when using a compatible adapter)
gfx 35mm format menu

That’s the quick-and-dirty of the GFX 35mm Format Mode! Please let me know if you have any questions.

Check out the Fujifilm GFX50S II Tutorial Course to learn more about all of the other menu options and operation of this awesome camera – use code “BLOG20” for 20% off!

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