selmslie Loc: Fernandina Beach, FL, USA

Although some might take umbrage at the term “Exposure Triangle” as being somehow misleading or inaccurate, trying to change its name is an exercise in futility. The concept is perfectly valid despite any controversy over its name.

The real problem is that discussion of the triangle commonly overlooks the most important consideration, the amount of light shining on the scene.

Here are two images taken on consecutive days. Both images were taken at ISO 400 with white balance set to Daylight in the camera.

The camera’s meter was not used to determine the exposure settings. Instead, I used a Light Value (LV) setting of 12 on the heavily overcast day and an LV setting of 15 for the image in full sunshine.


Heavy overcast - recommended LV is 12


Full sunlight - recommended LV is 15


Settings used for LV 12


Settings used for LV 15

Note that the histograms for both images show no blown highlights and they are both close enough to the right to produce a good JPEG SOOC.

The most striking difference is the dynamic range of the two images.

The overcast image needs no shadow recovery and might even benefit from an increase in contrast.

The full sun image might benefit from a little shadow recovery but that's optional.

User ID

Maybe there’s a problem with my browser. I cannot see any comparison pix of the same scenes as exposed using the camera’s onboard metering system.

selmslie Loc: Fernandina Beach, FL, USA

I seldom use the camera's meter because it can make mistakes.

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So no baseline for the examples ?

Would be useful to see the same scene suffering the errors of spot, matrix, and center weighted metering by comparison.

selmslie Loc: Fernandina Beach, FL, USA

The posted images are the baseline.

Think about it.

burkphoto Loc: High Point, NC

Scotty, I fully agree. The term, “exposure triangle,” is flawed. Put a balloon in the center. “Fill it with photons...“ The sides then stretch to adjust sensitivity, exposure time, and aperture.

The shape changes to emphasize or deemphasize the relative effect of each variable.

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They can be used that way. The posted pix as baseline, contrasted with posted pix that show the deficiencies of camera based metering. That would speak to all users who need to switch to LV charts as a solution to their erratic camera governed results.

Initially it bugged me to see no baseline but now I have accepted that there is baseline ... but an unused baseline, as no variables are compared to it. The baseline just sits uselessly in a vacuum.

I have a paper target with its bullseye completely shot away ... no other holes ... that proves the value of resting the gun on a beanbag. But without the accompanying target with holes scattered all over it ... shot without a beanbag ... the target with the blasted out bullseye would prove nothing concerning the efficacy of the beanbag.

It’s the same test result regardless of which target is declared to be the baseline.

Ysarex Loc: St. Louis

Right. With rare exception photographers use and rely on light meters. For good reason.

Joe

Ysarex Loc: St. Louis

So the concept is perfectly valid but....



Oops! and the real problem is..... Off to a great start.

Joe

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The show must go on.

The tent is afire, elephants stampeding, tigers eating children, but the Human Canonball will not be denied his moment.

selmslie Loc: Fernandina Beach, FL, USA

The relative effect of each variable is the same:

[aperture log value] + [shutter speed log value] + [ISO log value] = [light value (LV)]

or A + S + I = L

That's why the triangle works, regardless of the labels.

burkphoto Loc: High Point, NC

No disagreement there. The flaw is that the area inside the triangle isn't recognized as the LV... Changing the shape without changing the area merely indicates the balance of the ISO vs speed vs aperture.

selmslie Loc: Fernandina Beach, FL, USA

Here is another example for broad daylight and LV 15 taken at 12:26PM:



The fountain is now on so there are a handful of specular highlights (maybe 20) in the image. The sun is higher in the sky so there is no large dark area in the foreground. The scene's DR is much narrower than earlier (8:40 AM).



I changed the ISO and the exposure but the LV is the same as the morning image.

selmslie Loc: Fernandina Beach, FL, USA

You only need to put an "LV=15" label in the center. Or whatever LV is calculated from the three settings.

That sounds like an incredibly simple app for someone to write. Anyone interested? They can use my spreadsheet as a source for the formulas. I'm afraid it's not going to generate much revenue.

srt101fan

Scotty, with all due respect for your technical knowledge, the camera does NOT make mistakes........Your constant references to the meter making mistakes, not being as smart as you, etc, is the wrong thing to say to novices.

It's like telling radiology students that X-ray machines can't be trusted because they can make mistakes. Radiology students just need to learn to interpret X-rays. Novice photographers need to learn how to interpret what the meter tells them and then decide if it is giving them values appropriate for their images.

BTW, not trying to be a smartass or confrontational, but you started a new topic here. After reading your first post, I am wondering what you are trying to say.

Most of us, I think, drawn in by the topic title, would like to see some practical bits of knowledge that we can apply to our photography. Could you please summarize the point you're trying to make in your opening post. If all you want is a sparring match with tables, numbers and equations thrown back and forth, OK, I can understand that. But is there more?