another one, fill flash doesn't change camera exposure 😁
"exposition" meaning other variables (iso/asa , scene brightness) are required to set camera exposure.
June 15, 2023
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No, that's one's right. Pretty basic.
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Prefer 'lightness'. 'Brightness' suggests emission of light. Further, 'lightness' is a defined term in terms of colour space, 'brightness' isn't.
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Yes, that's an error.
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Fair enough - every day is a learning day
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error in what ? fill flash never changes my exposures when shooting portraits or anything for that matter. its fill, it fills the shadows. does it change scene lightness ?
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Exactly.
Those who decide to stop learning end up as dunces. -
It changes the exposure value for that part of the scene where the flash is applied. Whether that changes your exposure of the scene or not depends in part on how you are metering it.
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[deleted]
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If we're talking camera settings, may I add Exposure Compensation? and even Flash Exposure Compensation?
Not to mention WB, Color Space, Color Mode and all them JPEG settings ...
In other words, considerably more than just three variables affect "image brightness" ....
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Well, I guess it is on those who want to learn to figure out who they should be learning from.
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How do you suggest to calculate image brightness for raw data?
Or image lightness?I'm asking because raw is defined over a non-colorimetric colour space, and thus, in "colour science" terms (lightness being the appearance of luminance L), lightness can't be defined when colorimetry (CIE XYZ) isn't defined; while brightness depends on the monitor settings (viewing conditions, more generally).
The way I see it, lightness is set during raw conversion and further image processing, whatever is the sensible definition of lightness that we accept.
Brightness is a different matter IMHO. -
I would put both of those under the broader category of metering.
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Iliah - I'm afraid your getting way to technical for me - I'll need to sit down with an ice pack on my head and read your full response slowly about 20 times!
In my defence, I was simply poking a little fun at DonaldB - not sure why I did that - I guess the urge just got too great
Tim
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OK, but the matter you brought up is pretty serious and IMHO deserves a discussion.
The point I'm tying to make is that the look of the image in terms of brightness and lightness strongly depends on the raw converter, raw conversion parameters, and image viewing conditions, not on exposure only.
Noise, however, is more or less a different matter.
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My own approach is to a critical learner. That is, take no-one as an oracle. When you learn something, work through it and see if it contradicts itself, or other things you know. If it contradicts itself, at least some of it is wrong. If it contradicts knowledge that you already have, then either it or your present knowledge is wrong.
All this body of knowledge depends ultimately on the concept of exposure. It's fairly easy to see which version of 'exposure' is correct. You can trace the history, you can look at which definitions are well founded, in that they have precise definitions which are consistent with other pieces of knowledge. Once you know what exposure is, you can see how other pieces of supposed knowledge either succeed or fail to fit with it. -
They certainly are side effects. The function of the ISO control, as specified by ISO standard 12232, is to provide a specific lightness (value) for a given exposure. No other function is defined or mandated, therfore cannot be 'ISO'. They are side effects of teh ISO control, and what they do varies from camera to camera. If you believe otherwise, please frame a statement which is a general and easy to understand description of what these other effects are, and what is the relation (in a formal mathematical sense) between them and ISO number. You will not be able to do it.
I would have though that what ISO says ISO is has some importance. Otherwise, what is your point of reference for what it is? As for needing to know what it does in your camera, are you suggesting that we need a different beginners' guide to ISO for each camera brand and model? If not, what are you suggesting?
And you think it is not becuase you're incapable of handling anything more than basic concepts. See how it works? Shall I suggest that we both agree not to assume demeaning motives for the other, and accept teh possibility that the other might be discussing from a position of understanding? You know, I can take this both ways. If you want to discuss it in terms of insults, I can do it better than you.
[ There is something about algorithms of encoding, etc., in information theory, which do not apply here. Insisting on it is pseudoscience. Here is what I wrote months ago at dpreview: Shannon's theory is about channel capacity, defined in a probabilistic way: the highest information rate with "good" coding algorithms, and one gets that almost all of those coding algorithms are "good".
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And what you have when you trace the reception of image data from a sensor through the processing chain is an information channel. So channel capacity is exactly and precisely what all this is about. It's certainly not 'pseudoscience'. I was about to add something there, but for the moment I'll make a first move towards not framing this discussion in terms of insulting caricatures of what the other is saying. -
?? ISO and brightness ??
ISO modify the way the e-picture is registered electronically, there is no better way than to describe it.
ISO is one of the first thinks that will disappear forever in photography.
WHY?
Because:
films were limited by emulsion sensibility, you shoot a roll then you change it, DLSR was limited by the dynamics of the sensor.
BUT
ML >NEW< better sensors and NEW >better software< will completely avoid to write noises in a very huge range.Auto ISO is like the angle of injection/ignition in an engine.
I was able to tune cars perfectly using some very fine table some 50 years ago, in '70.Nowadays there are 8 billion on the planet that may drive happily a normal car.
No more than 1.000 then can tune an engine manually. Nobody needs to: The engine's computer takes care of that.( time changes things set in stone - the old guard defends borders that are no more )
If you think I'm wrong > 8 Billion people can take a good/normal picture with a cell knowing NOTHING abouth light
while mother in 1960 was burning one pic after the other with her folding Kodack, a gift of my father
he knew less than her in photography but got better shots.
