Exposure triangle explanation please.

[AnthonyL]

Lots of references to the exposure triangle (ISO/Shutter Speed/Aperture). Now, I am comfortable with the relationship between the 3 elements, but has anybody got a good explanation of how to use the triangle to define the relationship and how to use the triangle?

 

[texinwien]

Limburger wrote:

Again, please be specific about how such a change would benefit crop-sensor cameras more than it would benefit full frame (or medium format or any other format) cameras.

With a small sensor you hit the wall quicker and would reveal the benefit what you try to point out quicker.

What wall? We need to know each sensor's saturation sensitivity and the amount of read noise. Everything else is physics. There is no imbalanced benefit for smaller sensor cameras to getting rid of the confusing ISO conceit.

You're an excellent example for why ISO should be done away with and replaced with something more intuitive. It's quite obvious that you have a very tentative understanding of ISO. It's obviously a confusing topic to you, based on your words in this post. If the topic is confusing to someone like you, who obviously has a lot of experience with photography, well, I can't think of a better proof that we need to replace it with something more intuitive.

And going to your final image, on screen or print would anybody notice?

Notice what?

The final medium I think should be thrown in as well.

Thrown into what?

 

[Guidenet]

texinwien wrote:

You're an excellent example for why ISO should be done away with and replaced with something more intuitive. It's quite obvious that you have a very tentative understanding of ISO. It's obviously a confusing topic to you, based on your words in this post. If the topic is confusing to someone like you, who obviously has a lot of experience with photography, well, I can't think of a better proof that we need to replace it with something more intuitive.

I may not understand it in the same manner as you do intuitively, but I think I understand it from a basic nature. As I said, when you aren't being somewhat aggressive, you are very helpful. Keep that in mind. Nobody here is attacking you. We are all learning together, or at least I do and am.

I don't find the idea of what ISO is in a digital world to be confusing at all. What I find to be confusing is the need to change the current model. Maybe my understanding of the change is not well formulated, but that doesn't mean I don't understand the implementation of ISO in a digital workflow. I'm also very fluent in concrete mathematics. Please don't talk in the pejorative. You will find it's not needed for me to be understanding and receptive to other's ideas.

One thing I don't understand is when you say people are forced to consider gain up front. As I understand it, you do not. You set base ISO and leave it there. Is that right? Given that, do you sometimes have issues with the embedded Jpeg being visible to be able to check other attributes? Also, is the RAW capture being currently saved without gain being applied except in the metadata for later application, if any?

 

[texinwien]

jrtrent wrote:

texinwien wrote:

Why should I choose the gain applied before I take the photo? There's no good reason to if you're shooting RAW and applying the gain yourself later on.

The biggest reason I can think of is because I don't want to apply the gain later on. I want the pictures to be completed in camera so that when I get home, all I have to do is download them to a sub-directory on my hard drive and enjoy a slide show on my monitor.

Understood. There are a couple of ways to do this. You could, of course, have the option to choose a target gain up-front. Or you could let the camera guess. And you could then be given the option to adjust the gain, in-camera, after you record the exposure.

I'm not saying it should be impossible to choose the gain before you record the exposure. I'm simply saying that we shouldn't be forced to choose it beforehand, and we should be able to adjust it (even in-camera) after the fact, if we so choose.

So I'm talking about removing constraints and adding possibilities without removing any options that are currently available

Once this is possible in-camera for JPEG shooters, the concept of ISO is simply confusing baggage that can be jettisoned.

Possibly, though I doubt that I'm the only JPEG shooter who wants to avoid rather than embrace later manipulation of the images.

Totally possible to continue doing that in my scheme

 

[texinwien]

TTMartin wrote:

texinwien wrote:

TTMartin wrote:

texinwien wrote:

JTC111 wrote:

texinwien wrote:

It's already not necessary on some cameras. On my current camera, I almost always shoot at base ISO. I ignore the ISO completely.

Add this capability to the ability to quickly adjust an exposure's gain in-camera, and ISO is simply thing of the past. Good riddance

Two questions:

If you " almost always shoot at base ISO," as you've stated in at least two different posts, then you occasionally do adjust your ISO setting, right?

As I posted elsewhere, my camera is ISOless above ISO 800. It has ISO settings up to 25,600, but since it's ISOless above 800, I ignore the higher settings.

So analog gain of the sensor changes the sensors ISO, but, digital manipulation of the image of the image after capture doesn't?

I can agree with that.

As a RAW shooter, I also only use ISOs that are created by analog amplification of the sensor. I have partial ISO steps disabled in my camera, and do not enable the expanded high ISO.

Think about how you'd operate if you only had a single ISO. If everything but base was created via digital amplification.

Until all output media matches that of your theoretical ISOless sensor, where the midpoint of the exposure in terms of the output media will need to be set.

So if I am shooting a JPG photo I might want the bottom 8EV of your theoretical ISOless sensor, represented by the 8 bits of my JPG file. I need to be able to tell the camera to do that.

ISO settings are the most familiar tool available to photographers to choose that point.

That's the wrong way to think about it. All you're saying here is that you would choose, for some arbitrary reason, to throw away light. You would choose to degrade the image's SNR without any reason, whatsoever.

Capture as much light as you can - you can fake added noise or grain in a noise-free image, but you can't coax real detail out of a noisy image.

Capture the best exposure you can and choose which bits go into the JPEG later on. Why choose a substandard exposure up-front?

 

[Limburger]

texinwien wrote:

Limburger wrote:

Again, please be specific about how such a change would benefit crop-sensor cameras more than it would benefit full frame (or medium format or any other format) cameras.

With a small sensor you hit the wall quicker and would reveal the benefit what you try to point out quicker.

What wall? We need to know each sensor's saturation sensitivity and the amount of read noise. Everything else is physics. There is no imbalanced benefit for smaller sensor cameras to getting rid of the confusing ISO conceit.

You're an excellent example for why ISO should be done away with and replaced with something more intuitive. It's quite obvious that you have a very tentative understanding of ISO. It's obviously a confusing topic to you, based on your words in this post. If the topic is confusing to someone like you, who obviously has a lot of experience with photography, well, I can't think of a better proof that we need to replace it with something more intuitive.

And going to your final image, on screen or print would anybody notice?

Notice what?

Benefit.

The final medium I think should be thrown in as well.

Thrown into what?

The equation.

If one can't discribe something short and clearly one probably doesn't understand it too well.

 

[JTC111]

Guidenet wrote:
Maybe my understanding of the change is not well formulated, but that doesn't mean I don't understand the implementation of ISO in a digital workflow.-
Cheers, Craig

An artist doesn't need to know why paint sticks to the brush, he just needs to know how to use the paint that sticks to the brush and when to reach for a different brush.

 

[texinwien]

JTC111 wrote:

texinwien wrote:

JTC111 wrote:

You say its useless but you use it. And you refuse to explain why you use this useless tool.

One of us is certainly being obtuse ...and it ain't me.

I said it is useless on an ISOless sensor. I said my sensor is not completely ISOless, but many new ones are, and, I think most will be at some point in the near future.

Not sure what's so hard for you to understand about that. It's completely clear and logical.

But it doesn't answer my "why" question. So let's try this another way. You say you vary your ISO settings from 100-800. Why not just leave your camera set permanently at 800 since that would effectively give you the ISO-less camera you very much desire?

Two reasons:

1. This would mess up the camera's ability to warn me correctly about highlights I am about to blow. It's more important to me to have this function work correctly.
2. I use Lightroom to process my images. There is a finite amount of exposure adjustment allowed in lightroom. Leaving the camera set to ISO 800 at all times would result in images where the highlights were too bright to recover using Lightroom's standard settings

If my camera were ISOless, I'd leave it on ISO200 all the time. I often leave it on ISO200 even when it gets too dark - the gains made from using ISO400 or 800 are minimal, anyway.

 

[texinwien]

TTMartin wrote:

texinwien wrote:

Abundant dynamic range is not necessary for an ISOless world to make sense.

Clearly you haven't thoroughly thought this out, and at this point are just making wild, nonsensical statements.

That's incorrect. I've thought through it quite well, and my statement stands.

I'm done.

Too bad - it seemed you were grokking things reasonably well. You're walking out on the truth here One of these days, when ISO disappears, you'll remember back to this discussion and say, "man, that guy was right, after all - wish I'd stayed and hashed it out with him."

Your loss