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Author Topic: X-Trans issue?  (Read 2496 times)

armand

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X-Trans issue?
« on: March 18, 2018, 01:17:59 PM »

I was testing my Nikon 50ish lenses and then I decided to give a go to the Fuji and Oly.

The X-T2 shot is sharper but I see a lot of weird artifacts, any idea what this is?
Can't say I've noticed them before. Lens was the 35/1.4 but I did see something similar on the 35/2 also. I can also see them in the jpeg so it's not LR. Look at the letters.


As a side note I also tested the Olympus E-M5 with the 12-100. At the wider aperture it has also some color artifacts that improve with stopping down but sharpness goes away then. The best is the high resolution shot, see a crop from the jpeg (the raw is bigger, not necessarily sharper).

I attached 100% center crops to see the issues including a "reference" shot from D750.

armand

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Re: X-Trans issue?
« Reply #1 on: March 18, 2018, 01:21:38 PM »

For the X-T2 issue it's easier to the at the lines 1878 and 1880, the letters are "chewed up".

The Oly has the words in alternating yellow and blue color highlighting.

Telecaster

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Re: X-Trans issue?
« Reply #2 on: March 18, 2018, 05:03:32 PM »

I'm gonna guess the artifacts are due mostly to aliasing, with a little additional demosaicing "jitter" in the Fuji's case. I saw a similar effect with small text on some signs & maps I photographed with my E-M1 in Grand Canyon Nat. Park back in 2014.

-Dave-
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armand

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Re: X-Trans issue?
« Reply #3 on: March 18, 2018, 05:13:11 PM »

For the Oly it's unusual, maybe the attached picture is not that clear, I increased a little the contrast and saturation to make it more obvious.
I'm not sure why it would have issues with something so basic?


For the Fuji I suspect it's related to the x-trans pattern interpretation, particularly as it is present in the jpeg also. What I'm concerned about is that it might be introducing false detail while eating some that exists already.
If I'm willing to let this go than with Fuji I get sharpest shots. If the scene doesn't have movement then the high resolution E-M5ii shot is the best, quite clearly so.

SuperNiceNina

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Re: X-Trans issue?
« Reply #4 on: April 02, 2018, 06:20:14 AM »

Hello Armand,

About the time of your post I invested in a Fuji X-E3 to supplement full frame Canon. I was initially worried I'd made a mistake as my files also displayed artifacts.

I process using Lightroom and it seems that Adobe's default acutance settings (algoritham) are not best suited to Fuji X-Tran sensors.

See http://thephotofundamentalist.com/fujifilm/help-sharpening-x-trans-iii-files-adobe-lightroom/ & http://petebridgwood.com/wp/2014/10/x-trans-sharpening/ for more.

Hope it helps you. Once I'd sorted this aspect out my X-E3 Fuji sings. As well as the full frame and 120 Velvia scans.
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rdonson

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Re: X-Trans issue?
« Reply #5 on: April 02, 2018, 08:05:28 AM »

Iíve tested the demosaicing performance of Lightroom for a couple of years.  Itís gotten better over time with Fujiís guidance but itís still not best of class when it comes to sharp results for X-Trans. I use Iridient Developer and X-Transformer and think the results are significantly better with regards to sharpness.

I still use Lightroom but for critical sharpness Iridient out performs it.

Pete Bridgewoodís recommendations worked on the X-T1 files but not so much on the X-T2.
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Regards,
Ron

TommyWeir

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Re: X-Trans issue?
« Reply #6 on: April 02, 2018, 11:32:56 AM »

 I can't speak to LR, but what I've heard is much as Ron discussed.

With the X-T2 I find that Iridient Developer is definitely the way to go.  I mainly use Capture One and there's a noticeable improvement in sharpness and detail when I use Iridient Developer.  I find that I collate and organise in Capture One, then I raw develop the images I intend to print in Iridient, and then finesse them and print from Capture One.  A more seamless workflow than it seems on paper.

armand

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Re: X-Trans issue?
« Reply #7 on: April 02, 2018, 03:51:15 PM »

I am familiar with those processing guides amongst others and that's not it, I tried several things.
I'll give some attention to Iridient in few weeks, long ago what I've seen from internet samples wasn't what I wanted; there was some increased apparent sharpness but colors were not right. We'll see what happens with the above samples and others.

rdonson

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Re: X-Trans issue?
« Reply #8 on: April 02, 2018, 08:23:49 PM »

If you're going to seriously try Iridient please be aware there is a small learning curve.  If you'd like to get through the learning curve as expeditiously as possible I highly recommend Thomas Fitzgerald's ebooks on Iridient Developer and Iridient X-Transformer.  His ebooks are very reasonably priced. 

Personally I mostly use X-Transformer as it fits nicely with my use of Lightroom and how I shoot.

https://store.thomasfitzgeraldphotography.com/product-category/e-books/
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Regards,
Ron

DP

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Re: X-Trans issue?
« Reply #9 on: April 02, 2018, 08:43:54 PM »

but colors were not right.

you do not need to use Brian's camera profile(s) if you don't like the colors even in Iridient Developer - create your own (Iridient supports both dcp and icc/icm models)

or for example use X-Transformer to linear DNG and then use your own profiles in ACR/LR or Adobe's obtained from Fuji (hardcoded in ACR/LR)
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