Exposure Triangle

[amolitor]

What is UP with this "exposure triangle" idiom? Every beginner's guide to photography web site seems to have picked this thing up, but it makes no sense to me. Don't get me wrong, I understand exposure just fine, thanks. It's the use of the triangle that's a mystery to me. At best it seems to capture the idea that "ISO, shutter speed, aperture are interconnected" which I can accomplish with the sentence "ISO, shutter speed, and aperture are interconnected" or with any number of graphical representations.

Is there something I am missing? If I, I dunno, imagine that the correct EV is a dot somewhere inside the triangle.. then when I adjust the shutter speed.. the dot.. I dunno, moves away from something and toward something else?

The triangle strikes me as a glib little bit of graphical crud that obscures the issue. Newbies stare at it, I imagine, and try to figure out what on earth a triangle has to do with anything.

Exposure is trivial, we don't actually need little mnemonic devices to teach it, and we CERTAINLY don't need anti-mnemonic devices like meaningless graphics.

 

[JAC526]

People like pictures man.

Don't give people too much credit.

 

[SCraig]

What is UP with this "exposure triangle" idiom? Every beginner's guide to photography web site seems to have picked this thing up, but it makes no sense to me. Don't get me wrong, I understand exposure just fine, thanks. It's the use of the triangle that's a mystery to me. At best it seems to capture the idea that "ISO, shutter speed, aperture are interconnected" which I can accomplish with the sentence "ISO, shutter speed, and aperture are interconnected" or with any number of graphical representations.

Is there something I am missing? If I, I dunno, imagine that the correct EV is a dot somewhere inside the triangle.. then when I adjust the shutter speed.. the dot.. I dunno, moves away from something and toward something else?

The triangle strikes me as a glib little bit of graphical crud that obscures the issue. Newbies stare at it, I imagine, and try to figure out what on earth a triangle has to do with anything.

Exposure is trivial, we don't actually need little mnemonic devices to teach it, and we CERTAINLY don't need anti-mnemonic devices like meaningless graphics.

Yes, there is something that you are missing. The geometric relationship of a triangle is that no single side or angle can be changed without making a compensating change to another side or angle. The same exact relationship exists between shutter speed, aperture, and ISO.

If you don't like it then don't use it. It's not going to stop others from teaching it that way though.

 

[tirediron]

First of all, I would submit to you that exposure is NOT trivial; it is the most critical aspect of photography. In fact, you could go far as to say that exposure is photography. The use of the triangle stems from the fact that there are three separate components to exposure, and they are inter-related. If you change one, then you have to change at least one other one.

The interior space of the triangle is irrelevant, it's the legs that are important. Assume that in situation 'X', ideal exposure is: ISO 200, 1/250, and f8. At that exposure, each leg is 6" long. We decide for the sake of the image that we need to have a shutter-speed of 1/1000; when we dial that on, it makes that leg now 12" long and "breaks" the triangle. Therefore we have to adjust the length of the other legs to compensate.

At the end of the day, if it doesn't work for you, don't worry about it.

 

[tirediron]

Get outta my head Scott!

 

[SCraig]

Get outta my head Scott!

Great minds think alike

 

[pgriz]

Whatever gets the idea across... Having people refer to the "Exposure Triangle" does not discombobulate me or impact my life in any way. Although I suppose, for sake of accuracy, we need to define whether it is an equilateral triangle, or an isoceles triangle or an obtuse triangle... And whether the space is Euclidian or Gaussian. Guess it doesn't matter if you use Powerpoint, which draws almost all trianges as equilateral, the easier it is to attach labels to the vertexes. Meh. Like "lines" of sight, and "square" meals, and "circular" reasoning.

 

[amolitor]

Yes, yes, I get that it captures the idea that the three things are interconnected. My point is that it seems to capture nothing whatsoever ELSE.

It looks like a graphic that I ought to be able to use to calculate, or at any rate estimate.

tirediron says:

"we need to have a shutter-speed of 1/1000; when we dial that on, it makes that leg now 12" long and "breaks" the triangle"

which is fine except that: a) the ISO, shutter speed, and aperture are invariable shown at the corners, so which leg is it exactly that got twice as long? and b) When we've got that sorted out, what are we supposed to do with the other legs? Make them twice as long as well by doubling the aperture and ISO? Or do we adjust the opposing angle instead which is.. what? Does the triangle have to remain equilateral, what exactly does it mean when we double the length of a leg, are we making the aperture bigger or smaller?

It FEELS like it's a geometrical model of what's going on, and that the triangle somehow captures something, but it simply doesn't. You wind up in a maze of 'well, the shutter speed is the angle so when you halve the shutter speed you have to double the angle no wait you cut it in half and then you have to adjust the sides no wait the angles OR the sides or or or oh god what is going on here'.

 

[Solarflare]

The three parameters ISO, Aperture, and Shutter Speed each have different properties.

Learning to know these properties helps to find the optimal values for these parameters for each picture.

ISO, you always want that at minimal value unless its completely unavoidable to raise it. If you have to raise it, it will introduce noise into your picture and limit all other parameters of your fotosensor, like dynamic range or color depth or resolution etc, as well.

Aperture, you want this very open if you need a small depth of field, like for a portrait. This also gives you the maximum light. However, if you want a very wide depth of field, you need to close it, massively reducing the available light.

Finally, Shutter Speed defines how much time will pass during taking your picture. If you just want to photograph a landscape, or some other static object, its not problematic. Just get a tripod and you can raise the shutter speed to seconds and minutes easily. In other cases, you want one specific shutter speed. For example for panning you need a very specific shutter speed that still allows to make the subject look sharp, but the background blurry, while you move the camera with the subject. Other times you want everything to be sharp. Then very low shutter speeds might be required, like 1/1000s and less.

So yeah, the exposure triangle is a very important to know about. If you take your picture with ISO 100 and f/2.8 will result in a very different picture from taking it with ISO 6400 and f/22.

 

[amolitor]

Just as a for instance, suppose we forget ISO for the moment.

Imagine a graphic of a teeter-totter, a see-saw, or a balance scale. Label one side "shutter speed" and the other "aperture", and then write underneath it "keep the scale balanced to keep the exposure the same". Now we see clearly and unambiguously (assuming we have proper labels) that if we make the shutter speed faster, we must make the aperture wider, and vice versa. It's an actual geometrical model of what's going on. The Exposure Triangle seems to be an attempt to extend the balance scale picture to include ISO, and it's failed completely.

Or at any rate, I have not seen a single explanation that managed to get any further than "here's the exposure triangle. These three settings are interconnected. Let's look at some examples!"

 

[SCraig]

Just as a for instance, suppose we forget ISO for the moment.

You can no more forget ISO than you can shutter speed or aperture. There ARE three factors involved, not two. Each with distinct advantages and disadvantages.

 

[Buckster]

What is UP with this "exposure triangle" idiom? Every beginner's guide to photography web site seems to have picked this thing up, but it makes no sense to me. Don't get me wrong, I understand exposure just fine, thanks. It's the use of the triangle that's a mystery to me. At best it seems to capture the idea that "ISO, shutter speed, aperture are interconnected" which I can accomplish with the sentence "ISO, shutter speed, and aperture are interconnected" or with any number of graphical representations.

Is there something I am missing? If I, I dunno, imagine that the correct EV is a dot somewhere inside the triangle.. then when I adjust the shutter speed.. the dot.. I dunno, moves away from something and toward something else?

The triangle strikes me as a glib little bit of graphical crud that obscures the issue. Newbies stare at it, I imagine, and try to figure out what on earth a triangle has to do with anything.

Exposure is trivial, we don't actually need little mnemonic devices to teach it, and we CERTAINLY don't need anti-mnemonic devices like meaningless graphics.

I wouldn't stand for it, if I were you. You should drop everything else and devote your life to destroying this terrible idea of the "exposure triangle". It's truly that important.

 

[amolitor]

AAAAAA

I do understand exposure, people. Please stop assuming that I don't.

 

[Phototripper]

For anyone that wants to practice exposure techniques, check out CameraSim (CameraSim | SLR Photography Demystified). This is a great way to experiment with various camera settings and see the results immediately.

 

[manaheim]

That's it. We need to ban the triangle! Who's with me???



Actually I never knew what it was before now. Sounds like a nice graphical way to demonstrate a concept. People are naturally more visual creatures so it makes sense that this would be helpful to many folks. If it isn't necessary for you then you're likely just well beyond needing it, so don't worry about it, move on... And remember it exists for when you need to explain it to someone more visually oriented than you.