Adobe's Fujifilm X-Trans sensor processing tested

With the posting of ACR 7.4 and Lightroom 7.4 'release candidates' (RC), Adobe has updated its raw processing algorithms for Fujifilm's X-Trans sensor cameras, the X-Pro1, X-E1, X100s and X20. This move comes in response to months of online user requests for improved raw processing of the X-Pro1, Fujifilm's flagship mirrorless interchangeable lens model.

It is rare that Adobe's Camera Raw team revisits its demosaicing process for previously supported cameras, so we were excited to try out this latest version with some X-Pro1 raw files and compare results to the previous version of ACR, Capture One Pro 7 and Fujifilm's own in-camera conversion.

To provide some context, the vast majority of digital cameras ever made perceive color using what's known as a Bayer Color Filter Array, named after the late Kodak engineer Bryce Bayer. For its recent cameras, Fujifilm has developed its own color filter array pattern, which it calls X-Trans. The idea behind X-Trans is that its pattern repeats less often than the Bayer pattern, rendering redundant the low-pass filter that usually protects against moiré.

The common 2x2 'Bayer' pattern used in most digital cameras.	The 6x6 color filter array pattern of Fujifilm's X-Trans sensor.

The disadvantage of creating a non-standard color filter array (especially one that took two years to develop the demosaicing algorithm for), is that third-party software makers have to do a lot more work to provide Raw support. Adobe was one of the first third-party software makers to provide Raw support for the Fujifilm X-Pro1, but the results often fell short of the standard set by the camera's own JPEG engine, in terms of rendering fine detail. So let's see what changes Adobe has made.

Adobe Camera Raw 7.4 RC support

What follows are comparisons of ACR 7.4 RC's rendering against the previous generation of ACR support, Fujifilm's in-camera JPEG engine and Capture One Pro 7's processing.

ACR 7.4 RC vs ACR 7.3

We use these crops to compare the defaults settings of ACR 7.4 RC with those of Adobe's original X-Pro1 support as processed in ACR 7.3, also at its default settings. Click on a full scene thumbnail for the original resolution image.

Adobe Camera Raw 7.4 RC: Click for the original full resolution image.	Adobe Camera Raw 7.3: Click for the original full resolution image.
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In the ACR 7.3 rendering, the foliage takes on a distinct 'watercolor' appearance, and the white text of the sign is 'filled-in' green. As you can see, the new processing approach in ACR 7.4 RC offers substantial improvements in both areas. The foliage has a natural, realistic appearance and the lettering on the street sign is color accurate. If you look carefully, you'll see that these improvements come at the cost of a marginally softer looking file, but the difference is small enough to be easily overcome with more aggressive sharpening applied.

Adobe Camera Raw 7.4 RC: Click for the original full resolution image.	Adobe Camera Raw 7.3: Click for the original full resolution image.
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In the studio scene comparisons, we see very similar results with regard to the presence of minor moiré and other aliasing artifacts. The ACR 7.4 RC rendering does offer a more neutral color response, avoiding the slightly warmer tint of earlier ACR support. And as we saw in the samples above, ACR 7.4 RC appears just a bit softer but does avoid the unnatural edge artifacts in fine detail textures found in the ACR 7.3 output. Taken as a whole, these samples show just how substantial an improvement Adobe has made in version 7.4 RC.

Click here for Page 2, with comparisons against camera JPEGs and Capture One