the result becomes a system overall performance.
... which is exactly what we should care about.
So the overall performance should include the entire camera, ie. noise, ISO, FPS, AF, lens, etc., not represented by DXO only.
It has been well known in the astrophotography that Nikon does NOT output real raw data, some degrees of NR is applied to their RAW.
This is a good point, something I didn't want to get into earlier b/c of the complexity of the issue. But since you brought it up... what one can do is actually fit the quantitated data from the RAW file (of the wedge shot) to the theoretical luminosity curve of the wedge. You can then find the point at which the fit deviates significantly from the model, & set that as your lower end. To standardize results, maybe set a 'maximum deviance' criterion. From this fit vs. model you can also detect 'shadow crushing'... that is, if data is significantly clipped on the lower end (as some suspect is the case for Nikon RAWs), the quantitated data will deviate from the model quicker (instead of continuing to be linear on a log scale, the quantitated data will level out). I've done these measurements for a D7000 vs. my 5D II & 5D III; both cameras show this 'toe' on the darker end, & even if you pick the lower acceptable end based on this toe, the D7000 is still ~2 stops better than any of the 5D series bodies.
This hokey stick type of curve looking like a check mark will tell you what the minimal DN vs Electron of the sensor is, it is again at least the overall of the QE+Opamp gain+ADC gain+processor algorithm. The processor can do a magic trick here to minimize the noise. I do agree, by inspecting Nikon vs Canon photo, that Nikon is better than Canon on the algorithm of this, they used another method. However, this does not mean the two sensor is of that much difference. DXO score does not indicate the sensor performance, as they claims, and this is my point. I think many of us are mislead by DXO score. Nikon, or Canon, or any one can design their camera targeting the DXO score if they want, but with bad actual picture, refer the following notes.
Let's put another grey color filter, there is no maximum white to be represented by the sensor any more
- First of all, that's an extreme case.
- Secondly, of course there's still maximum white... you adjust the exposure. Like I said, you take exposures right around the exposure that blows the brightest patch. An ND filter, e.g., simply does not trip up this methodology whatsoever.
What you do is to find the max and min of the electrons (photo) the sensor takes. You method can eliminate the effect of the optics, and I hope you did NOT use camera's shutter/aperture/ISO in this test. But, the problem is explain as my direct quote from another forum dvxuser.com:
"trez 04-25-2012, 04:06 AM
Speaking about DR, people often mix two things - the ratio of the brightness and the ratio of the coded values (digital numbers). These are not interchangeable terms.
Imagine 1-bit codec. The value can only be 1 or 0. Now, this doesn't mean much, unless we know which brightness levels that "1" corresponds to.
In general case, the camera has to squeeze its DR (or part of it) somehow into the available bits. There are various ways to achieve that and none is perfect - one of the reasons we have so many gamma curves. Assume 8-bit codec - even linear gamma curve can squeeze more than 8 f-stops into them - all it needs to do is to 'compress' the brightness range, so that, f.ex. digital 255 represents the brightness of 12 f-stops above what's represented by digital 0. It's just the mapping.
The problem is that the more we compress, the worse the tonal resolution becomes in the mids (and shadows), which is of great importance, f.ex. for skin tones - there's risk of severe banding, when there are not enough distinct (coded) levels to smoothly represent skin gradation. That's why non-linear gamma curves are used - they assign more coding space (distinct values representing various brightness levels) to where it makes more sense, taking into account things like logarithmic tonal perception of human vision, anticipated viewing conditions, noise, gradability, being able to use standard displays for monitoring etc. F.ex, LOG-based gammas sacrifices easy monitoring in order to improve on other areas.
So, while 8-bit codec doesn't necessarily limit the DR it can represent, there's no point in squeezing too much DR into it, as severe banding will occur in post, if we're trying to stretch it to get back to the original scene DR. Of course, some compression is fine - we don't need too much tonal resolution in highlights so we can squeeze them - this is similar to what film does, known as "shoulder".
I just don't see how you can say the DXO score IS the sensor only properties.
I never claimed anything of the sort.
Good, we are on the same boat then.
to downsize the picture? What a joke to these downsize from nikon, first, why not you downsize both 5D3 and D800 to 800x600, I bet they will be the same. To be extreme, we can downsize any photo to 1x1 size and all picture will be same for same the scene and exposure. Second, are you buying a 36MP camera and use as a 22MP each every time?
Since this has been covered extensively in other threads, I won't belabor the point... but, in a nutshell, the point is simply that the 36MP camera offers you the advantage of more resolution if you want it, while giving you just as clean images at the resolution of the 5D Mark III.
I will say though that it would've been nice for Nikon to include mRAW functionality for lower resolution RAW images right off the camera to ease the workflow of photographers. But that has its own issues, since mRAWs require demosaicing prior to downsizing (and so you don't benefit from the freedom of choice of demosaicing algorithm, or the evolution of such algorithms in the future). So perhaps it behooves RAW converters (ACR, Aperture, etc.) to offer this option in their software as we get higher & higher megapixel cameras... but that raises other issues -- e.g. do you save the original RAW file or not?
I don't clip/reframe my photo too much, I don't need THAT much MP unless I am a spy. You finish your composition before the shutter, do you? if not, you are really not a photographer. BTW, any MP greater than 10MP is fine for me already. You may say my lens is not a tele so I have to shoot than enlarge. Well, if you can no see, you can not shoot, simple as this. Again, I am not a spy.
BUT, I do need higher ISO and FPS, such as D7000, 7D, 5D3, etc.