"Overexposure means the important details in highlights are lost to clipping" - that's overexposed areas contain important details.
I wasn't talking about turing [sic] any knobs.
You tried claiming that overexposure means details are lost.
As an astrophotographer I personally find noise generated in the camera to be the big problem. That is why we cool the camera first and then take a series of shots with the lens cap on that we then subtract from the actual astronomical images, which greatly reduces the noise in the final images. Shot noise does not come into it.
You are presuming that ALL images have highlights and that those highlights contain important details. If an image does NOT contain highlights (e.g. a low-key shot) then overexposure CAN be TOTALLY corrected. End of story.
Why? It's the same, brightness adjustment. But I'm happy that you agree that changing brightness doesn't change exposure.
It's over-processed (over-brightened).
The Earth is clearly flat.
That's a lame argument in a debate.
Here is from your advice, https://www.dpreview.com/forums/post/63158448 :
What, where, why?
A low-key shot may contain highlights, only those are usually small. For example, the first shot in Wiki article https://en.wikipedia.org/wiki/Low-key_lighting contains 3502 pixels at level 255. They are important, to establish contrast and to play at how we perceive images.
Meaning, unimportant highlights are blown out, and then the brightness is toned down to form featureless grey areas? I don't see how that results in the same image quality as starting from a better exposure. Could you provide an example, please?
Seriously? And I was hoping for examples and explanations... Am I out of luck?
That would be a new use of "over exposure".
Astrophotography is a special case. The issues facing an astrophotographer may not be the same as those facing most photographers.
So when too much light hits the sensor and the picture looks brighter than intended, calling that 'overexposed' is new?
It's new to digital photography. With analog photography, over exposure didn't result in a lighter print. Typically the print had a lower contrast, or looked wrong as it hit the wrong part of the film's response curve.
"Over exposure" is an exposure that is higher than what you desired. If your goal is to minimize overall image noise, then you should shoot raw, and use the highest exposure that doesn't blowout highlights that you wish to retain. If that's your goal, then Iliah is correct.
Thank you very much for the clarification Michael. Yes you are 100% correct
This is very interesting
Exposure triangle attempts to explain how to change shutter speed, aperture, and ISO setting in accord in order to maintain the lightness of a shot when the light is already measured.
I know you think you are being very smart an amusing but a particularly dim wombat would see that you are trying to cover your embarrassment at being wrong by doing the Professor John I.Q. Nerdelbaum Frink Jr. routine, which simply makes you look sad.
Too silly for words. You are simply rehashing the age old exposure triangle and turning it on it's head. Are we supposed to be baffled by your inverse logic? Grow up.
The physics and the process are IDENTICAL, as are the major issues.
What has depth of field got to do with it? We are talking about image noise. And I note that you don't contest my facts.
It is done in special astronomical software that basically adds the "dark shots", as they are called, together and then subtracts the result from the image. We also take "white shots" of an even light source and use them in a similar way to correct for deficiencies in the optical system and sensor.This is very interesting
Can you please elaborate a bit on how you subtract the lens cap shots from the astronomical images.
Is it as simple as putting the 2 images on top of each other in separate layers with the blend mode set to "Difference"?
How do you know what I think? Is it possible that you are mistaken?
A dim wombat would in fact see exactly that; my target audience is on a different level
The difference is that in astrophotography the light levels are low enough that the camera noise is a significant factor.
My point was that the article was not about astrophotography. In astrophotography, depth of field is usually not an issue. With many other genres, depth of field is a factor to be balanced. This is another example of how the balance of factors is different for astrophotography.
Thank you very much for your explanation.It is done in special astronomical software that basically adds the "dark shots", as they are called, together and then subtracts the result from the image. We also take "white shots" of an even light source and use them in a similar way to correct for deficiencies in the optical system and sensor.This is very interesting
Can you please elaborate a bit on how you subtract the lens cap shots from the astronomical images.
Is it as simple as putting the 2 images on top of each other in separate layers with the blend mode set to "Difference"?
Many digital cameras actually have a noise reduction mode built in that works in a similar manner for long exposures: taking a second exposure with the shutter closed and subtracting the resulting noise. Check your cameras manual.
