What is advantage and disadvantage between X-trans vs Bayer array

Started Sep 7, 2013 | Questions thread
Randy Benter
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Re: What is advantage and disadvantage between X-trans vs Bayer array
In reply to ealvarez, Sep 7, 2013

Most digital cameras use an OLPF (optical low pass filter) in front of the sensor to reduce moire effects caused by repeating patterns. While the OLPF does reduce moire, it is essentially just an optical blur filter, so it also reduces sharpness and details in the image.

In X-Trans cameras, Fuji chose to eliminate the OLPF and instead use a unique CFA (color filter array) to reduce moire. Theoretically, the removal of the OLPF will allow the image to retain more sharpness and details. However the special CFA requires more complex demosaicing algorithms with additional software filtering in order to produce an image that is free of artifacts.

I compared images taken with my 16MP Nikon D7000 and 16MP Fuji X-E1 using the same lens and found that both these cameras produce the same amount of sharpness and detail when processed for optimum results. One camera uses an OLPF and the other requires more demosaic filtering. The end result is essentially the same.

Many believe that X-Trans images produce less noise at high ISO than Bayer images. I can easily see how one could reach this conclusion if viewing the DPR comparison tool or other poorly implemented comparisons. I compared the high ISO noise of the D7000 and X-Pro1 and found them to be very similar. The X-Pro had perhaps a 1/3-stop advantage, but that is not enough to make a practical difference.

I believe my test results were different from DPR for two reasons. 1) I compared images with the same shutter speed and raw exposure level. This might mean comparing Fuji ISO 3200 to Nikon ISO 2000 for fair results. 2) I processed both images for optimum sharpness and noise reduction. This means using different settings in LR for each image. The default rendering of the X-Trans image will have less noise, but will also have less sharpness and details. The default rendering of the Nikon image will be the opposite. Once you process them both for optimum results you will get very similar images.

While I find the X-Trans output to be very similar to Bayer output, there is the occasional image where the X-Trans demosaicing algorithm will smear fine details. This has been discussed fervently for many months on this forum. The situation has improved greatly with the latest releases of Adobe and other processors (like CaptureOne). At one point the general rule was to use the OOC JPEGs for best results, now the consensus seems to favor raw for best results. Either way, most of the images I shoot (but, not all) do not have any problems. Only certain images will be affected, generally with foliage or hair or other fine detail that is just the right size to get smeared by the algorithm.

So even with the improvements, X-Trans processing has been a point of frustration for me. I have been using LR/ACR for years; I prefer Adobe tools and 3rd party compatibility, but I sometimes need to use other processors (C1) to get the printed results I want from X-Trans images. My workflow has become convoluted, but I love the feel and controls of my Fuji cameras. I do not want another brand of camera, but for me X-Trans does not provide enough benefit to be worth the processing issues. I will continue to use my current X100 and my X-Trans X-E1 while I await further processing improvements or an X-Pro 2 sans X-Trans. I will also continue to recommend Fuji cameras to others.

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