There is RAW data (light as recorded by the camera's sensor);
Could you please explain what do you mean by the above?
he meant the raw data was a representation of the light that was seen by the camera's sensor.
So is JPEG (one can take an OOC JPEG and "calculate back" the light values in the scene), and in a sense, anything else that faithfully (subjective) gives a viewer the impression of the scene.
Yes, that's a reasonable statement. As an overview, values in both raw files and JPEG files flow from the light hitting the sensor.
But I think we are losing sight of the context of the statement. I believe he was trying to differentiate between the data that flows from the pixels and the metadata. In that context, it seems to me, that his usage was correct.
If highlights are clipped in raw, how to describe the representation, as limited? What if shadows are plugged? In the absence of light, given exposure is long enough and ISO setting is high enough all that gets out is noise. What does raw data represent in this case? I'm not even going to mention many other factors, distorting the "representation".
Again, you are losing site of the context. You seem to be suggesting that one can't generally refer to the data derived from the sensor unless one completely describes the technicalities and limitations of that data.
Such a level of detail may very well be critical if you were writing software that processed raw files. However, it seems needlessly complicated if one is simply trying to describe in a beginners forum that some data flows from the sensor pixels, and some does not (i.e. the metadata tag that contains the photographer's name).
One could say that raw represents the scene better than JPEG, but even that isn't an absolute given.
Again, I am not sure how this is relevant to a discussion as to which camera settings affect the raw file.
How, or even
if, those setting affect the resulting JPEG isn't really on topic.
There is no simple or single answer to the question what is raw data. As of today, raw data is what the camera manufacturer says it is.
Again, I think you are trying to get into the weeds on a topic where a general overview is called for.
And even than...
Adobe are
suggesting the following: "RAW files contain uncompressed and unprocessed image data", but what is image data? Is normalization (artificial black level, ISO, white balance pre-conditioning, noise reduction, etc) allowed here and isn't considered processing? Is lossless compression considered no compression? Are files recorded in a lossy compressed mode are raw in name only?
I think in the context of the OP's question, it is sufficient to say something like "the image data reflects what the sensor's pixels saw. The exact format, content, and meaning of the data varies with camera models."
If you want to go into a little more detail, you can certainly mention that the various ways the data might have been manipulated (lossy compressed, lossless compressed, noise reduction, scaling, etc.).
Consider what Nikon are
saying: "RAW image files ... contain all the image information captured by the camera's sensor, along with the image's metadata (the camera's identification and its settings, the lens used and other information). The NEF file is written to the memory card in either an uncompressed or 'lossless' compressed form." OK, how are we supposed to understand 'lossless' here? As true lossless, or as visually lossless? What is "image information", and what is not?
And before I bow out, some types of raw data (most notably, with Canon) include non-image data (buffers, optical black, etc.).
Ciao.
Imagine that you were trying to teach someone how to drive a typical new model car. You can tell them that when the car is in gear, pushing on the gas pedal makes the car go faster. Many people would think that this is a sufficient generalization for someone who wants to learn to drive.
On the other hand, you could point out that this isn't really the case, Most cars have some sort of transmission. The gas pedal generally feeds more gas to the engine, this may make the engine turn faster. Depending on how the gears change, a faster turning engine may result in a slower moving car. You could even point out that some cars have automatic transmissions, some have manual transmissions, and some electric cars have neither. In some hybrid cars, the gas pedal is connected to electrical motors, and the gas engine is controlled by a different system. While all of these are true (and I have left a lot of details out), the beginner may be better off with the rule of thumb that pressing the gas pedal makes the car go faster.
In the context of the OP's question, I don't think there is a benefit to a long discussion on how simply referring to data from the sensor can be misconstrued.
But's that just my opinion. I hope that if the OP found your detailed corrections helpful, he will chime in and correct me, and thank you for the clarifications.
