"Pros always use Manual exposure, A and S are for amateurs ..

Started 4 months ago | Discussions thread
Michael Fryd
Michael Fryd Veteran Member • Posts: 9,632
Re: "Pros always use Manual exposure, A and S are for amateurs ..

AwesomeIan wrote:


Pushing the exposure in post is very much the same as increasing the ISO in camera. In the example above its actually worse because the Mark IV doesn't have ISO invariance. Whatever the case, setting the cameras sensitivity to light (i.e. ISO) is a fundamental part of getting correct exposure. Sure you can shoot at ISO 100 in good light and not have to touch the ISO (even in post) but that doesn't change the fact that adjusting the ISO is often used to get correct exposure. Thus it being part of the exposure triangle.

Actually, ISO does not change the camera's "sensitivity to light". If the light level is too low to register at ISO 100, it still won't register with the camera set to ISO 128,000.

What the ISO does is set the mapping from the light that was captured to image brightness.

Now, I'll grant you that for simplistic purposes, a beginner might think of ISO as controlling the sensitivity, but as he gets more advanced, that can lead to misunderstandings and bad choices.


As far as post-processing being able to change the "exposure", that's sounds like time travel. "Exposure" happens when you take the photo. It's not something that can be changed after the fact.

Suggesting that "Exposure" is something that can be varied later on, is turning the traditional definition of exposure on it's head.

This definition raises some interesting questions. If I make a print, and the print fades, does the fading reduce "exposure"? If I turn up the brightness on my monitor, does that increase "exposure".

It sounds like you definition of "exposure" has little to do with the image capture process, and is simply a property of the final image.

Do a google search on 'exposure triangle' and see the overwhelming majority (if not all) agree the triangle is shutter, aperture and ISO.

And a Google search for "what is photographic exposure" will suggest that the proper definition is the light reaching the sensor.   The simplistic beginner tutorials play fast and loose with the terminology, and do sometimes talk about an exposure triangle.  Scholarly papers, and advanced discussions consider "exposure" to be the light falling on the sensor/film.


As Richard Feynman pointed out, many people used to think that the planets orbited the sun because "there were angels behind them beating their wings and pushing the planets around an orbit."

This explanation is certainly good enough for simple questions, but it is fundamentally wrong, and isn't helpful in complicated scenarios. However, if you understand that planets orbit due to the interaction of inertia and gravity, then your model becomes really helpful.

Thinking of "exposure" and "image brightness" as being the same is like thinking angels push the planets around the sun. At a very simplistic level it sort of gives you an idea of what's going on, but the model isn't helpful for real understanding.

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