X-trans vs Super CCD Dynamic Range performance

Louis Scarole wrote:

I keep using my S5 Pro beside much newer cameras, even if it is way behind in terms of resolution and high isos. Reasons are DR and colors.

At DXO scores, the S5 is still a very good performer for DR today. If you look at the measurement graphs, the S5 shows an almost constant DR from 100 to 800 isos, decreasing slowly from 13.5 at 100 isos to 12.8 at 800 isos. The D810 rank at the first place in DXO mark at 100 isos (14 Ev), but it decrease very rapidly (11.3 Ev at 800 isos).

DXO doesn’t provide any scores for X-trans sensors, and I wonder if the X-trans sensor is doing better than the S5 in terms of DR. My impression is the S5 is still the best Fuji camera regarding DR.

This is not a trivial question because the S5 used the dual pixel tehcnology with every other pixel being partially masked to make it artificially less sensitive. This improved the dynamic range drasticly, while the drawbacks were lower sensitivity and higher noise as well as possibly other stuff like increased pattern noise etc.

The X-Trans sensor is a off the shelf Sony sensor, so you can use Sony's ILCs, like NEX-6 as a substitute for the Fuji - any DR differences are minor.

If we think of the engineering DR, the DR DxOMark measures, then yes, S5 Pro likely has higher DR than any other Fuji camera.

However, and this is a big however: the photographicallly usable DR is quite different. The engineering DR has noise floor of SNR 1, ie. the DR is the range between sensor saturation and the point where signal to noise ratio is 1. SNR 1 is way noisy beyond normal photography.

What is an acceptable noise floor for a photograph? That is of course a very personal thing and depends on many parameters. We might for example consider 20dB SNR to be barely acceptable, thus if we define that as the noise floor, the tables turn and the X-Trans ends up having much better photographically acceptable DR. If we consider SNR of 18% gray (middle gray), the current Fujis are about 1.5 stops better than the S5, and the difference gets even larger if we go into the shadow range. Thus the Old S5 hits it's "acceptable minimum quality" threashold much sooner than the modern camera.

In short - if you have no image quality threshold, the old S5 Pro has excellent DR at low to mid ISO. However, for actual photographs the X-Trans typically has larger DR.

(Note, the above assumes no pattern noise - the Sony sensor has practically no patter noise. I have no idea how much the S5 has, being old and being CCD. If I has to guess, it has some and this can have dramatic effect on the usability of the shadow range of the DR.)

Anyhow, the old S5 was an interesting and innovative product - very popular among wedding photographers in it's day cause of the DR advantage against the competition of the day. But time's moved on.