Demonstration of X-Trans Under-the-hood RAW Spatial (Noise) Filtering

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tradesmith45 Senior Member • Posts: 1,752
Demonstration of X-Trans Under-the-hood RAW Spatial (Noise) Filtering
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Some of us over in the Astro forum have been taking a close look at some Fuji camera sensor characteristics. For those of you who don't follow this, astrophotographers have been discovering under the hood RAW data filtering in many Sony sensor based cameras. The well known star eater problem has been found in some Sony & Nikon cameras. An algorithm is applied to find and remove hot pixels & it frequently mistakes stars for hot pixels. Fuji seems to be doing something different.

An avid astrophotographer asked about the performance of the X-T3 & this sparked a very revealing group examination. The reason I posted here is these findings may explain the waxy/wormy artifacts & RAW converter choice/settings frequently debated in this & other Fuji forum. A star field provides an excellent way to examine these questions.

We've found that Fuji applies filtering to X-trans RAW data in camera that slightly smooths images & produces some star color artifacts but no filtering is used in the Bayer sensor X-T100. This is easily seen by comparing X-T2/3 images w/ X-T100 images. The later is much sharper. Ironic isn't it?

For many/most users & for web display, the difference will not be noticeable.  And the filtering seems to only apply for longer than 5 sec. exposures.

The differences between RAW converters handling of X-trans is trivial compared to the difference between X-T100 & X-T2/3. There is no way to turn the filtering off & Fuji has never disclosed this.

This is also how we found that electronic shutter & continuous drive modes in Fuji cams bin the RAW data down from 14 to 12 bit.

For a comparison of astro image results look HERE.

For a deep dive into Fuji sensor analysis, look HERE.

Not looking to start any war about X-trans just hoping to clarify what's going on. Hope its helpful.

 tradesmith45's gear list:tradesmith45's gear list
Fujifilm X-T2 Olympus E-M1 II Fujifilm X-T20 Olympus M.Zuiko Digital ED 60mm F2.8 Macro Samyang 12mm F2.0 NCS CS +5 more
Fujifilm X-T100 Fujifilm X-T3
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