Como hoje surgiu numa discussão um assunto que me chama a atenção pelo desconhecimento geral em cima de algo que notóriamente não é verdade; A dificuldade do XTrans de reproduzir detalhes em folhagens, resolvi compartilhar um comparativo sobre este assunto que considero um dos melhores já escritos. Vamos lá:
Is the latest 24MP X-Trans III sensor ‘Good’?
….Nothing beats a proper comparison with a conventional ‘Bayer’ sensor, using a variety of challenging real-world subjects. So that’s that I’ve done, concentrating in this article on how well the X-Trans III records various types of details of a variety of sizes, relative to the sensor’s pixels.
Many of you will have read my Part One reviews on the Fujifilm X100F and the Fujifilm X-T2. Some will perhaps also have seen the lens performance and detail crops in my evaluation of the X100F’s 23mm f2 Fujinon lens. These will have given you a decent idea of final image quality at low ISOs. However, what it didn’t do was give you an idea of how a camera with a Bayer filter on top of its sensor would have fared in comparison.
A Little X-Trans Background
For those familiar with all this, skip ahead to methodology.
The original Fujifilm X-Trans and X-Trans II sensors were both 16MP. Some people complained about ‘the watercolour effect’, or were not happy about the resolution of green foliage or fine detail. While we know that some of these issues came down to the way Adobe software was rendering the RAW files, its important to note that the X-Trans array is fundamentally different to the Bayer array on the vast majority of sensors. The diagrams below make this clear (see how the reds and blues are in less of a checkerboard pattern, the two sizes of green blocks and larger overall proportion of green).
Fujifilm went to some trouble to produce the X-Trans design and the supposed primary benefits are reduced moiré, higher resolution (due to the lack of an Anti-Aliasing/Low Pass filter) and more ‘organic’ looking noise (due to the less uniform distribution of red and blue pixel filters). Whether these benefits are real or not is another matter, but for this article I am looking to poke and prod at the possible Achilles heel of the newest 24MP X-Trans III. I am looking at fine textures and fine green details, because these have been associated with criticisms of the X-Trans sensors of the past.
I will be honest and up front: I was in the camp that felt the X-Trans sensors of the past created at least as many problems as they solved. I could not care less how good Iridium developer is, or Photo Ninja, when I own numerous other cameras and I’m wedded to the day to day workflow provided by Lightroom. That’s of course a very personal perspective, but one I still feel is right for me. There are enough complications in life and work without having to run multiple workflows for different cameras as a matter of routine necessity (rather than occasional luxury).
So, has anything changed?
The fair test would be to see how the Fujifilm X-T2 files compare to those from a 24MP APS-C Bayer camera using comparable lenses. However, this seemed a little boring. After all, the Sony A7 II is comparably priced to the Fujifilm X-T2. While the Sony A7 II isn’t as responsive or fast (and the lenses are generally larger/heavier) it does of course have a larger sensor. It is also a Bayer sensor. This unfair test seemed a bit more relevant to me and perhaps will be of more interest to you. So, I pitted a Fujifilm X-T2 with Fujinon 56mm f1.2 APD against the Sony A7II with Zeiss Batis 85mm f1.8. Ouch.
Now to Discuss Methodology
The Lenses: The Zeiss 85mm f1.8 Batis is a phenomenal performer. It is exceedingly sharp, produces bags of contrast and really does get every drop out of the 24MP A7 II. However, the Fujifilm 56mm is every bit as sharp as the Zeiss optic in the centre of the frame, which is where all the below comparisons take place.
Apertures: I decided to shoot both lenses a few stops down from wide open, so that nobody would feel that one or other was being hobbled. Can we all agree that the Fujifilm 56mm f1.2 is rather good between f4 and f5.6 and that the Zeiss Batis 85mm f1.8 is also ‘on form’ between f4 and f8? I hope so! I have mostly shot the Fujifilm combo with a one stop wider aperture. This is because the smaller sensor and shorter lenses give roughly one stop more depth of field at the same aperture as Full Frame (FF). By using, say, f4 on the Fujifilm X-T2 and f5.6 on the Sony, we are using the sort of settings that a person may use when actually making real photos. Both lenses are absolutely singing here.
Stabilisation: The vast majority of shots were taken using a tripod. Those shot handheld were done without stabilisation on either camera and very high shutter speeds. I can assure you that all frames are as sharp as they get.
Shutter Speeds: In most cases, I tried to roughly match shutter speed on the two cameras. As the Sony was set to a smaller aperture and the Fujfilm uses a different ISO scale, settings might not seem comparable, however, trying to match shutter speeds seemed realistic to me, as this will often be the limiting factor for real world use. If the cameras are not at their base ISO (or either 100-200 on the Sony), it will be stated.
Other Imaging Details: You may also wish to consider the following:
The Sony has a quite different colour balance in most shots. It is more ‘yellow-green’ and saturated in this part of the spectrum.
The Zeiss Batis produces higher levels of overall contrast. In this regard, it could be seen as noticeably more ‘aggressive’ compared to the more ‘relaxed’ Fujifilm lens. While the Batis is likely to be used for mixed purposes, I suspect that most Fujifilm 56mm f1.2 (R or APD) owners point theirs at people. I have not adjusted for this in any of the files unless otherwise stated.
All of the below files are at their default settings, as imported to Lightroom. They were imported as RAWs and exported at the exact same resolution and quality setting as JPEGs. I have only added basic ‘sharpen for screen’ in the Lightroom export dialog box. I will show some sharpened examples later, but thought starting with the defaults was sensible. It isn’t perfect, but it’s a start.
I did not attempt to perfectly match exposures, as this is made all the more difficult by the different ISO calibration of the two cameras and different contrast levels of the lenses. Overall, the Fujifilm X-T2 tends to expose a bit further to the right.
Viewing: You will no doubt pixel peep and that is the idea. However, if you are viewing on a non-HD/Retina screen, you may find sitting back a bit more useful. 100 PPI will only give you a sense of what 60″/150cm prints might look like…
Photos Comparisons
Example 1: I chose this scene because it contains a mixture of organic (green) detail as well as man-made elements. There’s a variety of textures and detail here, not to mention colours.
Fujifilm f5.0 Whole Scene
Sony f7.1
Fuji crop
Sony crop
Example 1 Summary: I see a slight resolution advantage to the Fujifilm combo here, which is most obvious in the distant building in the top right of the crop, but also in the roof slates and bamboo fence on the left. This is mostly the A7 II’s Anti-Aliasing (or low pass) filter slightly softening the finest details. The fine green leaves take on a very slightly painterly effect on the Fujifilm file when inspected at 1:1, but when you reduce viewing to something more realistic (1:2/50%) this is not visible. You may also note slight moiré and false colour on the bamboo fence on the very left of the Sony file. This is absent with the Fujifilm.
Example 2: Fine green detail such a grass and leaves is most likely to give the Fujifilm X-Trans III sensor a headache if anything can. Let’s see what this medium distance example shows.
Fujifilm X-T2 – Whole frame
Fujifilm X-T2 Crop
Sony Crop
Example 2 Summary: The 24 MP Fujifilm X-Trans III sensor has recorded plenty of detail, it seems naturally rendered to my eye and the lack of an AA filter gives more bite to the Fuji file. Where the X-Trans III loses out is in the red/brown stems in the vegetation in the upper right of the frame. Both look a little different, but if we ignore colour balance and contrast differences (at default settings), the differences aren’t huge.
Example 3: What about broader green leaves, such as those in the centre of this frame?
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Fujifilm f4 Crop
O artigo continua no link abaixo para quem queira ler ele completo, no entanto como pode ser visto, não há nenhuma situação onde um sensor bayer se sobressaia a um Xtrans nos verdes ou nos detalhes de vegetação como reza a lenda popular.
O que vocês acham?
Fonte:
http://thephotofundamentalist.com/fujifilm/fujifilm-x-trans-iii-vs-bayer-texture-detail-comparison/
Espaço Fujifilm