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

tradesmith45 wrote:

saltydogstudios wrote:

tradesmith45 wrote:

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?

I've done a similar analysis and found the same. Though probably not as in-depth as yours.

Fuji seems to use an "area detect" smoothing algorithm that tries to find like areas & reduce contrast within those areas. This is just a guess.

I go into much depth about it here

https://medium.com/ice-cream-geometry/x-trans-vs-foveon-a-mostly-monochrome-photowalk-1a931f8fb277

The image on the left was taken with a Foveon sensor camera (and then upscaled), and the image on the right an X-Trans sensor camera with in ACROS color mode, it's the out-of-camera JPG.

Notice how "smooth" the bricks look on the right. I describe the difference as being like a charcoal drawing (left, Foveon) and an oil painting (right, X-Trans).

This is much reduced when processing in RawTherapee.

What you describe seems to be a more extreme version of this - perhaps that algorithm kicks into high gear at long exposures? Like... If this is Fuji's version of noise reduction, then it would stand to reason that when doing long exposures, their noise reduction does more of the same.

I don't do astrophotogrpahy, but I think I'm going to have to go spend some time over there, you guys are doing some fascinating stuff.

With regards to what someone else said - I haven't done any kind of analysis but my gut hunch is that the 16 megapixel generation X-Trans sensor didn't do this - or at least not as much.

Thanks for these comments & tests Salty. I'm on the road w/ only an iPad so can't dig into your images. Can't say if Fuji uses the same filtering for jpg & raw.

In my earlier tests did report that RAW filtering can be found in XT10 images too. Unfortunate. When I compared LRCC, RP & CP1, found no detail differences but did see they all use different color profiles. The XT2 was less likely to overdo green in the background w/. RP.

Yes, I'm not saying that Fuji uses the same noise reduction algorithms for JPG and RAW.

But if their noise reduction algorithm works the way I described - then if/when they turn it on for RAW I'd expect it to act in much the same way.