Re: Sony FX9 camera test
Alister, I have tested the FX9 camera with the S-cinetone curve with the value 320 ISO / 0Db
In the analysis of the Stouffer scale, the total RD with a value of 320 ISO is 9.37 stop and with a ISO 800 it is 9.78, that is, approximately a little more than 1/3 of a stop with this last value of ISO. Now, if we consider a certain amount of noise, for example, the medium value, which is the one that usually coincides with other RD tests, at 320 ISO is 9.97 stops, while with a value of 800 ISO it is 9.21, around 2/3 more stop. The average SNR for example in Y is 48.6, while at a value of 800 ISO it is 46.2, that is, an increase of 2.4 Db. The best signal-to-noise ratio is clear at 320 ISO which allows for that greater dynamic range. Now, I wanted to contrast that difference with a black and white texture chart to assess where I am missing the detail. In whites at 320, a little more detail is observed in the highlights, up to 4 1/3, while with 800 at that value there is already a slight loss of detail in some areas of the textures, although it is not yet clipping. in such a way that I would consider that the real difference between using those two ISO in the highlights is slightly more than 1/3 of a stop at 320 ISO. In the shadows the range really remains more or less the same, with 5 stops of detail, although at those 5 stops below the middle gray I have observed a little more noise at ISO 320. Actually, it seems to me that the range Dynamic at 800 "slides" down relative to 320 ISO and that shift could be over 1/3 stop. The difference with respect to the S-log3 curve seems to me to be still similar. Evaluating the medium gray in relation to the white of 90%, the medium gray is located as you indicated at 44% A value that is within the values relative to the STD curves.
If I consider the RD of the S-cinetone at 320 ISO it would be 4 above the medium gray and between 4 ½ and 5 below. If I consider the RD of the S-cinetone at 800 ISO it would be between 3 ½ or 3 2/3 and five below. The differences are not visually noticeable and it is necessary to go into detail to be able to see them. If an increase in sensitivity with the S-Cinetone curve is needed due to the existing light conditions, it is possible to work at 800 considering that small loss of RD in the highlights. The noise level in the shadows is good enough not to have an observable loss of image quality.
I really don't know if the differences we can find are worth it, but I think that taking the tests is a learning process, at least that's how I understand it, and it serves to understand, compare and ultimately to decide. It does not matter so much if the differences are great or not, but the knowledge itself that is obtained.
At present I believe that there are no great differences, nor great discoveries when we do camera tests and you have to go into a lot of detail to observe them. A famous Colombian boxer used to say that “it is better to be rich than poor”, and paraphrasing it we can say that it is better to shoot with a good camera than with a bad one, or that it is preferable to shoot with a very good camera rather than with a good camera, but The truth is that the difference in the image between a good camera and a very good camera is invisible to the viewer, and the difference will be in the look of the cinematographer, although it is true that improvements in cameras sometimes have no impact both in the image quality but in the options that the cinematographer has to work with. For example, with the FS7 excellent images are obtained as with the FX9, but with this we have the Dual ISO which is very practical.
In the end, we learn and learn as Art says in a bottomless pit… fortunately.
Let me know Alister if these results agree with your tests
Alfonso Parra ADFC
Tel Colombia 57 311 5798776
Tel Spain 34 639109309