Help with Shutter, aperture, and iso?

[petrochemist]

Doesn't ISO in digital just increase the gamma? That's how it seems anyways.

No, it turns up the amplification before the A/D conversion.
As the A/D converters used in cameras are typically 16bit precision or less, while the output from the sensor is analogue (it's actually quantized at the photon level, but in most photography there are so many photons recorded this is effectively continuously variable).

 

[petrochemist]

Basically the International Organization for Standardization allowed the Japanese camera manufacturers to write it for them.

That is the way these standards bodies work. If there is an existing method that works it gets adopted & standardized.
Once it's adopted it is difficult to get any changes made in the method. Some of the methods the panel I sit on (for hydrocarbon testing methods) have been adopted by ISO we can add a explanatory note at the start of our publication of the method if a problem or source of confusion comes to light, but to make changes requires a 5 yearly review at ISO to vote through the update.

Methods that have been adopted by ASTM can change much more rapidly - in at least one case I know about forcing the IP to come up with a fresh standard as the original was adopted by EN (the European standards body) & ASTM - who then changed it significantly...

 

[Ysarex]

I agree with you and I thought a lot about that in the last two days. What I could have done was to avoid the term "exposure" all together, and use image brightness only.

Ilford deals with that in the book I cited. They define exposure in the strictest and accurate terms in the proper place. But elsewhere in the book they devote a couple paragraphs to the need to have another term that won't cause confusion and they define for their own use in the book the term "camera exposure" which does include film speed. It's a book not a video and so it's easy enough to take up that quarter page to do that. I appreciate the difficulty here -- it isn't easy.

There's an online class out there presented through Harvard of all places and in one of the video lectures the presenter comes to the point where he has to give a quick explanation of what is ISO. You can see him wince and them stammer for a moment as he says something like, "well for now just think about it as changing how light sensitive the camera is." It was hard for him to do that; I could see he wanted to explain it, but he took the shortcut. Why not, Nikon does.

I need to think about that. Unfortunately as I said earlier, youtube won´t let me change a video that is already online. So I need to think whether I start all over, or live with a (I would still call it small - but I know you´ll disagree) incorrectness that is pretty common.

No I don't disagree and it's more than pretty common. The majority of people using cameras including many who use them seriously and professionally misunderstand quite a lot about how their cameras work and about photography in general. As I noted earlier even the camera manufacturers perpetrate the misconceptions. You can go to Canon's website and find the "exposure triangle" neatly presented and Nikon tells them ISO increases light sensitivity. And to a large extent it doesn't matter for the end result -- certainly not for enthusiasts who just want to take a nice photo. So you're right about that. One of the reasons I'm taking the time here is because I did watch your videos and I was delighted to see the ISO video. You didn't just repeat the standard nonsense "ISO alters the light sensitivity of the sensor/camera." And when you said ISO brightens the image I was applauding. It is in fact a post processing procedure that occurs after exposure. When you understand that it can really change the way you take photos -- so it really can matter. We're entering into a new tech phase where more and more cameras will be ISO invariant. I have a Fuji X-E2; I can ignore ISO.

Photography is full of similar misconceptions. Try discussing DOF in one of these forums. Read Petersen's book and find out how it doesn't work. You missed what I was getting at with the example about lens focal length. It's a common misconception that perspective is a function of the lens, eg. perspective compression gets attributed to the lens -- it's not the lens.

Beyond simply the satisfaction of understanding, it can matter a lot to get it right. Another story: 40 years ago I worked behind the counter in a camera store. I thought I understood DOF and was trying to explain a lens DOF scale to a customer. At the time I believed the common misconception that DOF distributed 1/3 front and 2/3 back around the subject, but I realized that lens DOF scale said otherwise. So later I asked the store manager who was a good photographer and he pulled a book off the shelf and handed it to me. It was an old 1940's vintage copy of the Leica Manual. He said read this and do the math. I did.

A few months later a wedding phototog came into the store holding a photo of open end wrenches shot from above at a 45 degree angle. He was trying to expand his business and pick up some illustration work. He shows me the photo and says it looked like he needed to get a 50mm for his camera (6x6) because he wasn't getting enough DOF from the 80mm. (In 1978 that 50mm was a $900.00 lens.) The wider angle lens would give him more DOF. I said, "If you switch to the 50mm won't you also move the camera closer to keep the same crop on the shot?" He said yes. So I told him that the DOF would be same with the 50mm. He put me in my place as a lowly camera salesperson -- he knew deeper DOF comes from wide angle lenses. I shut up and sold him the 50mm.

Joe

I don´t think it will make a difference for 99.99% of all the people with a camera.
There are so many other similar common misconceptions out there, and while I´m not a fan of contributing to that, I need to decide whether it does make a real difference to the majority of my viewers, or rather not.
Anyway - thanks a lot for your time and patience .

 

[robbins.photo]

So anybody else notice the OP ran screaming from the room a couple of pages back? Or is that just me?

 

[photo1x1.com]

I agree with you and I thought a lot about that in the last two days. What I could have done was to avoid the term "exposure" all together, and use image brightness only.

Ilford deals with that in the book I cited. They define exposure in the strictest and accurate terms in the proper place. But elsewhere in the book they devote a couple paragraphs to the need to have another term that won't cause confusion and they define for their own use in the book the term "camera exposure" which does include film speed. It's a book not a video and so it's easy enough to take up that quarter page to do that. I appreciate the difficulty here -- it isn't easy.

There's an online class out there presented through Harvard of all places and in one of the video lectures the presenter comes to the point where he has to give a quick explanation of what is ISO. You can see him wince and them stammer for a moment as he says something like, "well for now just think about it as changing how light sensitive the camera is." It was hard for him to do that; I could see he wanted to explain it, but he took the shortcut. Why not, Nikon does.

I need to think about that. Unfortunately as I said earlier, youtube won´t let me change a video that is already online. So I need to think whether I start all over, or live with a (I would still call it small - but I know you´ll disagree) incorrectness that is pretty common.

No I don't disagree and it's more than pretty common. The majority of people using cameras including many who use them seriously and professionally misunderstand quite a lot about how their cameras work and about photography in general. As I noted earlier even the camera manufacturers perpetrate the misconceptions. You can go to Canon's website and find the "exposure triangle" neatly presented and Nikon tells them ISO increases light sensitivity. And to a large extent it doesn't matter for the end result -- certainly not for enthusiasts who just want to take a nice photo. So you're right about that. One of the reasons I'm taking the time here is because I did watch your videos and I was delighted to see the ISO video. You didn't just repeat the standard nonsense "ISO alters the light sensitivity of the sensor/camera." And when you said ISO brightens the image I was applauding. It is in fact a post processing procedure that occurs after exposure. When you understand that it can really change the way you take photos -- so it really can matter. We're entering into a new tech phase where more and more cameras will be ISO invariant. I have a Fuji X-E2; I can ignore ISO.

Photography is full of similar misconceptions. Try discussing DOF in one of these forums. Read Petersen's book and find out how it doesn't work. You missed what I was getting at with the example about lens focal length. It's a common misconception that perspective is a function of the lens, eg. perspective compression gets attributed to the lens -- it's not the lens.

Beyond simply the satisfaction of understanding, it can matter a lot to get it right. Another story: 40 years ago I worked behind the counter in a camera store. I thought I understood DOF and was trying to explain a lens DOF scale to a customer. At the time I believed the common misconception that DOF distributed 1/3 front and 2/3 back around the subject, but I realized that lens DOF scale said otherwise. So later I asked the store manager who was a good photographer and he pulled a book off the shelf and handed it to me. It was an old 1940's vintage copy of the Leica Manual. He said read this and do the math. I did.

A few months later a wedding phototog came into the store holding a photo of open end wrenches shot from above at a 45 degree angle. He was trying to expand his business and pick up some illustration work. He shows me the photo and says it looked like he needed to get a 50mm for his camera (6x6) because he wasn't getting enough DOF from the 80mm. (In 1978 that 50mm was a $900.00 lens.) The wider angle lens would give him more DOF. I said, "If you switch to the 50mm won't you also move the camera closer to keep the same crop on the shot?" He said yes. So I told him that the DOF would be same with the 50mm. He put me in my place as a lowly camera salesperson -- he knew deeper DOF comes from wide angle lenses. I shut up and sold him the 50mm.

Joe

I don´t think it will make a difference for 99.99% of all the people with a camera.
There are so many other similar common misconceptions out there, and while I´m not a fan of contributing to that, I need to decide whether it does make a real difference to the majority of my viewers, or rather not.
Anyway - thanks a lot for your time and patience .

I would love to discuss on and on, and listen to your stories. But I think robbins.photo is right - we went "a bit" too far in this thread . Thanks for making me think again. I´m sort of a perfectionist (at least in my small world).

 

[astroNikon]

So anybody else notice the OP ran screaming from the room a couple of pages back? Or is that just me?

Yes I noticed that too.

but FWIW
ISO will now be known as .. A "visually identified number on the camera" that helps balance out the Shutter and Aperture to help attain a proper exposure.

 

[freddy21]

Understanding Exposure

We need a "Best Answer" option down with the Winner, Like etc buttons.

Any book that can have a raw amateur with their first DSLR shooting full manual inside the first few chapters gets my vote too. Great book and worth buying as a reference down the road too.

 

[clothrop]

I recommend reading these 3 articles to get better understanding of each element:

Understanding ISO: Understanding ISO - A Beginner's Guide
Understanding shutter speed: The Ultimate Guide to Shutter Speed
Understanding aperture: https://expertphotography.com/how-to-understand-aperture-5-simple-steps/

After you learned about each element, you should know how they all work together to form a beautiful image. The bond between 3 elements is called exposure triangle.

Learn more about it here: The Exposure Triangle: aperture, shutter speed and ISO explained | TechRadar

 

[Drive-By-Shooter]

This online course is based on one taught at Stanford University from 2009 through 2014.
Digital Photography

 

[Ysarex]

I recommend reading these 3 articles to get better understanding of each element:

Understanding ISO: Understanding ISO - A Beginner's Guide
Understanding shutter speed: The Ultimate Guide to Shutter Speed
Understanding aperture: https://expertphotography.com/how-to-understand-aperture-5-simple-steps/

After you learned about each element, you should know how they all work together to form a beautiful image. The bond between 3 elements is called exposure triangle.

Learn more about it here: The Exposure Triangle: aperture, shutter speed and ISO explained | TechRadar

I see you're new here. Welcome to TPF.

The OP who asked the question is long gone so we needn't worry about what he or she will see.

I'm old and retired and I try not to be too cranky but just for reference those articles are so wrong. I realize they represent the customary and colloquial way of presenting that info but that is not how our cameras work. Some of the problems with the misinformation in those articles is discussed earlier in the thread if you're interested. You'll have to make allowance for me I'm just tilting windmills.

Joe