Fuji LUT Preview vs Export: Why Photo Sizes Differ

A photo editor has two different jobs: show a useful view on your screen and produce an image file. FujiCam keeps its preview canvas separate from the LUT processing canvas, so changing the browser window does not change the downloaded photo size.

The three sizes to distinguish

Source size is the width and height of the decoded photo. Processing size is the image used for LUT calculations. Preview size is the viewfinder display buffer, based on its CSS dimensions and your screen’s device pixel ratio. The interface shows preview and export dimensions beneath the image.

Why the preview fills the camera

Fill mode enlarges the displayed image until it covers the viewfinder; edges may fall outside the visible area. Show full photo fits the entire image and may leave bars when aspect ratios differ. Both modes preserve proportions. Neither mode changes the export crop.

What the export limit means

The current processing limit is a longest edge of 4096 pixels, or a lower WebGL texture/renderbuffer limit imposed by the device. A 6000 × 4000 photo becomes approximately 4096 × 2731 on a device supporting that limit. A 2400 × 1600 photo remains 2400 × 1600. Smaller sources are not enlarged for processing.

A larger preview does not create detail

A small image can fill a large viewfinder, especially on a high-density screen. That display enlargement does not add source detail or increase export dimensions. Use the largest suitable original within the supported formats if fine detail matters.

What is saved in the JPEG

Export uses the complete processing canvas with the selected LUT and intensity, not a screenshot of the viewfinder. Grid lines, interface labels and preview bars are not included. Downloading while comparing the original still saves the selected graded look. The output is JPEG, so source transparency is not preserved.