« on: Today at 08:35:14 AM »
You can simply test your software. Switch to manual mode and take a photo of some dark objects before a dominant white wall and expose like the camera would do (make the white wall grey). Then expose to the right and remember how many EV you increased the exposure. E.g. 1/100s camera exposure vs 1/25s ETTR exposure = +2EV. Then use the RAW files and convert them with your software and apply -2EV exposure to the second picture. Now they should have EXACTLY the same color properties but the ETTR picture should have less noise. If not, your software is not up to that specific task.
At the end of the day the goal is to take a picture and to expose for that specific subject and the sensor noise may actually be low enough that you are satisfied with the exposure suggested by the spot metering of the camera. In that case you can directly use the camera JPEGs and be fine. Heavy postprocessing is only for low volume activities or people with too much time.
What a load of rubbish ! You have underexposed the White wall in the first place due to the failings of your camera (reflective ) meter ! Your 'ETTR' is only to get back to the correct exposure anyway.
I've said it many times; those interested in learning photography should get themselves an incident light meter and start to get to grips with exposure. (And the fact someone posts here suggests they are interested).
As for 'the' spot meter reading, this is another exposure error give away. The whole idea of a spot meter is to take multiple readings. One spot meter reading is likely as not to be highly inaccurate.