The Exposure Triangle Is Misleading And Unnecessary.

What matters to beginners and, IMO, working pros is simply this: “did I capture the image that I wanted/will this satisfy the client/will this sell?” Highly technical discussions, IMO, often don’t help the beginner and the folks making money off of their photography simply don’t care.

I don't know where that image actually came from, what settings were actually used or what post processing might have been applied to it, and so has nothing to do with my op.

The misconceptions that are thrown out - I am sure to help - but cause more confusion (and food fights on Internet forums today the exposure triangle is number one. It doesn't exist. Exposure has a physical definition. It is the amount of optical energy incident on a sensor - no more and no less. It doesn't matter if the sensor is film or silicon. It can be calculated by the it is the radiant flux received by the surface times the time of exposure ( in our case shutter speed). The units are given in J-sec/m^2. ISO - does not enter into any of these equations.

The second concept of importance is sensor sensitivity. Be it film, it is the amount of exposure required so that the results under calibrated development results in a detect predefined density. For digital it is the same as the definition for sensitivity of an optical sensor - the energy required to generate the minimal detectable signal. These are functions of the film and the digital sensor - largely determined by the materials, designs and semiconductor process used to generate the photodetectors on the sensor.

In the film days - the term ISO was falsely assigned to this film sensitivity. Now the original digital sensors were CCD's. A CCD was a semiconductor chip of photodetectors - a device that created a voltage ( collecting the charge) proportional to the amount of incident. This charge was marched off of the CCD for follow on processing. The amount of incident light energy necessary to generate the minimal detectable signal (charge) above the noise floor is the sensitivity. So somehow the concept of ISO was carried over. Wrong but no harm or confusion yet.

Then the CMOS sensor arises. All a CMOS sensor is a chip which merges the photodetectors with the follow on processing (the off chip electronics in a CCD camera). That is the signal conditions, amplification and analogue to digital and quantization to a digital word (14 bits in many of our cameras today). So instead of a matrix of charge marched off of chip, we have a digital frame of data. Exposure relates to light power. Where the confusion results is that the brightness one sees in a jpeg is not really a function of the exposure but of the signal conditioning - particularly the amplification (into the ADC) and digital amplification (through curves in the generation of the jpeg output). All of this processing is controlled by the "ISO" one choses. There is no exposure triangle. There might be a brightness triangle.

To talk about exposure one needs to consider the base sensitivity of the photodetectors in the sensor relative to the optical energy incident on the photodetectors. A appropriate exposure would be one that makes maximal use of the dynamic range of the photodetectors - a physical property of the sensor. However, that has little to do with the brightness of the jpeg. I can cut the light energy incident on the 3 dB (1/2) and get the same brightness by a combination of analogue amplification and digital amplification by 2.

The digital standard for ISO has noting to do with sensitivity - which is how the ISO standard arose when the sensor was film and amplification was not really possible.

So the evolution from film where "ISO" was more or less related to film sensitivity to light, was bastardized to some extent when the CCD EO chip came along but and then when the signal conditioning and amplification chip was integrated into the CMOS sensor - ISO evolved to have little meaning related to proper exposure.

If shooting sooc jpegs then yes.

If shooting raw and the aim is too maximise the quality of the raw data then:

1. set the smallest f-number to give the desired DOF.
2. set the slowest shutter speed that will meet blur requirements.
3. set ISO to Auto and let the camera set image lightness where it sees fit. Final image lightness is set in post.

If at base ISO important highlights are being clipped then you need to compromise on DOF and/or blur to avoid clipping.

If there is highlight headroom raise ISO, because the exposure* has already been maximised for the artistic constraints, to push the histogram data as close as possible to the right to where clipping of important highlights occurs.

* exposure - amount of light striking the sensor per unit area while the shutter is open
** optimal exposure - the maximum exposure* within dof and motion blur requirements without clipping important highlights.
*** under exposed - more exposure* could have been added with the DOF and blur constraints still being met without clipping important highlights.

Nikon disagrees : The ISO setting is one of three elements used to control exposure

www.nikonusa.com/en/learn-and-explore/a/products-and-innovation/iso-control.html

How?

You're just going round in circles now because that was raised either in this or another thread and it was explained that if you talk to any of the actual camera manufacturers' engineers, and not the marketing/sales people, they will not tell you that iso is an exposure control. The engineers there actually know what they are talking about.

Especially in Manual mode ISO has no effect on exposure* at all as has been shown in practical examples in numerous posts.

* exposure - amount of light striking the sensor per unit area while the shutter is open
** optimal exposure - the maximum exposure* within dof and motion blur requirements without clipping important highlights.
*** under exposed - more exposure* could have been added with the DOF and blur constraints still being met without clipping important highlights.

"3"/ triangle what do they have in common ?

except if you are using the z9

You are not answering. How does ISO control exposure?

That’s because he knows it actually doesn’t, especially in manual mode.

If he actually read the aricle he linked to he would have seen that they are defining exposure as how light or how dark a sooc jpeg looks and not as the correct technical definition as the amount of light striking the sensor per unit area while the shutter is open.

That’s because he knows it actually doesn’t, especially in manual mode.

If he actually read the aricle he linked to he would have seen that they are defining exposure as how light or how dark a sooc jpeg looks and not as the correct technical definition as the amount of light striking the sensor per unit area while the shutter is open.

That article is actually supporting my op where I say at best the exposure triangle is misleading because it teaches an incorrect definition of exposure and imo is totally unnecessary as I described.

Yeah, well don't believe everything you read on the internet.

Your link also contained this pearl of wisdom...

"Each time you double the ISO (for example, from 200 to 400), the camera needs only half as much light for the same exposure. So if you had a shutter speed of 1/250 at 200 ISO, going to 400 ISO would let you get the same exposure at 1/500 second (providing the aperture remains unchanged)".

Does that sound right to you? Gee, I guess might as well just shoot at ISO 12,800 and 1/2500" then. It's the same exposure, right? What could possibly go wrong?

Hmm, it's no wonder why it's so difficult to have proper conversation about this stuff? Way to go, Nikon!

Yep, they are confusing exposure with image lightness and assuming they mean the same thing when they are two different things.

They are incorrectly defining exposure as how light or how dark a sooc jpeg looks.

The funny thing here for me is that DonaldB has posted a link to an article that actually supports my op in that the ET is at best misleading and at worst total nonsense.

So, in this beginner’s forum, if we say that “high iso causes more noise” are we done with this nonsense thread?

And why should we say so?

Nikon really ought to do better.

It's kind of like walking into a hospital and noticing that there are a lot of sick people there and saying "hospitals make people sick."