... for an average scene, but not necessarily for a scene that includes light or dark or strongly coloured subjects (Kodak used to stress that, advising bracketing -1, -1/2, 0. +1/2, +1).
Actually, I think we've both misinterpreted what Iliah was saying,
I thought he was saying is was within 7% of 18% of maximum processed output.
Possibly you thought he was saying 7% of maximum processed output, as opposed to 18%.
Now I think he was saying 7% of maximum raw value. That would figure, because since the switch to Sony sensors Olympus/OM has been leaving enormous headroom.
It is interesting to note that there is no force "trying" to even these out, by looking at previous results. All of the absolute biases of the first 100 rolls remain no matter how many times further you roll the die; they just become a smaller proportion of the total. A "5" is no more likely for roll number 101 than a "4". If you randomly create lottery numbers to play, but forgot to play them and the numbers were picked, there is no rational reason not to play them for the next drawing, but there is also no rational reason to play them again, either.
When I go into NYC very early in the morning on the first bus, it stops at a Casino, and a lot of people that did an overnight in the Casino get on the bus. I hear some REALLY strange conversation after they get on.
Probably for another thread; I read your post and it doesn't say why, when you go to grab a camera for a particular use, you invariably choose one of the others over the Sonys. Longtime Nikon user is just curious...
Just guessing here -- it wasn't a rational decision.
I never cottoned to the Sony menu system.
I use a lot of Nikon F lenses (like the 105/1.4 and the 180-400/4), and there's no good Nikon F adapter for E-mount IMO.
The Z cameras feel better in my hands.
In a practical sense, that is going to depend a lot on your exposure strategy. If light is constant enough for you to keep up with manual exposure AND manual ISO, then you may only have to test the scene once to make sure you have no clipping, and until something brighter happens, your settings are good and you can be spontaneous. With blinkies, you would get a hard-to-miss warning as soon as it started getting brighter.
If you use an auto-exposure mode and/or auto ISO, however, you might want to back off a little more on ETTR than with full manual, as metering tends to run a little wild, even with current "intelligent metering", and even in consistent ambient lighting as different parts of the same overall scene are metered. You can see just how wild metering runs by looking at the passive meter in full-manual exposure/ISO mode as you point the lens at various parts of the environment, even when the lighting is even.
I would prefer "lightening" to "brightening".
If we use "brightness" for the scene and "lightness" for the viewed image (on-screen or print) things can be kept clearer.
For raw sooters, 18% is too high for digital sensors, which clip, as opposed to negative film, which has a shoulder. There's an argument to be made that 12.5% is too high.
I normally use matrix or evaluative metering. Hopefully this avoids clipping.
If you have a camera with a more sophisticated metering system, why not use it ?
In my Z 6, there are two matrix metering modes: regular, and highlight-weighted. The real difference is to where in the scene the exposure is anchored; in regular, it's to the middle gray, in highlight-weighted it's to the assemblage of highlights. I would surmise that, if your matrix mode doesn't have any qualifiers, it's anchored to middle gray...
I use my highlight-weighted matrix mode by default, knowing that it'll preserve the highlights I want preserved. It does let go things like intense in-scene light sources, but that's okay by me. @thom in his user guide recommends also setting a +2EV exposure compensation to take back some of the headroom it leaves, getting closer to a ETTR exposure. I haven't played with that yet, I just work the tone curve in post...
The more sophisticated the metering system, the harder it is to figure out what it's doing. And, IMO, the best ways to get the exposure right for raw are the zebras and the histograms, not any of the metering systems.
I took plenty of good photos with a Sony NEX-5N, but the Sigma cameras that I use now are I think nicer to use. Never used a Sony FF camera, but I've seen plenty of good photos from them taken by other people.
Only if you lose interest in where the raw highlight clipping occurs at higher ISOs. You may lose interest, because "only read varies" if you constrain exposure and vary ISO setting, but someone else may be interested precisely because read noise varies.
The 18% card positioned as Kodak are suggesting reflects ≈12.7%.
For meter calibration constants K=12.5 and C≈330 (Canon, Nikon):
reflectance R = 100 * π * K / C ≈ 12%.