Exposure Triangle

Not much brings out pedantic dickheads like a discussion regarding the so called exposure triangle. Wait, did I use the term “dickheads”? Yes, I did. And I mean it. For an example of what I’m talking about go read this at PetaPixel. It’s a great article that explains the exposure triangle and how it’s a tool to demonstrate three aspects of exposure in digital photography; shutter speed, aperture size and, yes, ISO.

After reading the article, if you peruse through the comments, you’ll begin to see what I’m talking about with comments like:

There is a very good reason to hate the triangle. It not only confuses people but its pure nonsense. ISO is not part of exposure. ISO is only applied after the exposure.

Increasing ISO reduces noise in most cases

No. Changing ISO does not change sensitivity.

This guy is actually saying that ISO plays no part of exposure.

That’s just simply incorrect.

Tony Northrup chimed in as well with:

Came here to say this. Great article, but I hate the triangle metaphor. It only confuses people.

Tony Northrup sort of has a point with regards to how this guy presents the exposure triangle, but generally speaking, for people just starting with digital photography, the exposure triangle is a rock solid way of understanding how exposure works vis a vis digital photography. By the way, if you’re starting out, perusing his site would be advisable. He and his wife Chelsea do a very good job of presenting helpful information.

You can visit just about any photography forum and when the subject of ISO and exposure comes up; especially when incorporating the exposure triangle, the dickheads come out en mass to bray that ISO has NOTHING to do with exposure.

Bullshit. If you hear someone say that, disregard them. They are incorrect. They are wrong. They are being pedantic dickheads.

Hell, even Nikon’s website says otherwise:

Aperture + Shutter Speed + ISO = Exposure

The three variables that make up a photographic exposure are shutter speed (how much time it takes to make the exposure), aperture (how big the hole is that lets light through the lens, and into the camera) and ISO (how sensitive the digital image sensor or film is to light).

Now, technically speaking, ISO may not be exposure. A lot of the pedantic dickheads will point out that exposure is the amount of time and light that is allowed to make contact with the sensor. So what. For all practical purposes, in the real world, exposure results in how the image will look; darker or brighter. That is determined by aperture size, shutter speed and ISO. Period. End. Of. Story. Don’t believe me? Try the following.

Get out your camera and set it on a tripod. Adjust the settings for optimal exposure. First set your ISO for, say 400. Perhaps your optimal exposure is then 1/250 f4.5 and the ISO has been set to 400. Take the pic. Look at it. It’s probably pretty close to optimal if your in camera meter shows the little mark at 0. Now, leave everything the same, but this time drop the ISO down to 100. Look at the camera’s internal meter. You’ll see that it is now left of 0; optimal exposure. Take a pic and look at it. You’ll notice that it’s underexposed compared to the first one. Now, do the same thing, but this time bump up the ISO to, say, 1600. You’ll see that the internal meter will show the little dot way to the right, and the resulting picture will be much brighter.

Furthermore, if you set it back to optimal, you can then increase the shutter speed and you’ll notice that the little meter dot is displaying an underexposed setting. You can then bump up your ISO to get the little dot back to 0. You can even take a pic if you like and verify it. You can do the same thing with the aperture as well.

The bottom line is that exposure is comprised of three variables: Shutter speed, aperture size AND ISO in every practical sense. This is why the “triangle” is such a good way to present it. If you make an adjustment to one you HAVE to make an adjustment to one of the other two (if your goal is to be close to optimal exposure). When some pedantic dickhead brays that ISO has NOTHING to do with exposure, then don’t believe your lying eyes. Do the steps above and you’ll see otherwise.

To address the pedantic nonsense that “technically” speaking, exposure is only the amount of time and amount of light coming in contact with the sensor, lets use this metaphor:

Many decades ago, in the US, we stopped using the gold standard. What this means is that our paper and minted money is no longer backed by gold. It used to be that gold was the thing of value that the paper and minted money represented. Without it, it was just paper and metal. Since the paper and metal is no longer backed by gold, technically speaking that crisp $20 bill in my wallet has no real value. It’s simply just paper, cloth and ink. Technically speaking it has no real value.

Except it does. If I can use it to purchase goods of value it has value even if technically it’s nothing more than paper, cloth and ink.

The same applies to ISO. It absolutely plays a part in how bright or dark (among other things) your image is. For all practical purposes, that is going to be interpreted as exposure.

So, who are you going to believe, some pedantic dickhead or your lying eyes and what every digital camera manufacture says?

The exposure triangle. Learn it, know it and embrace it.

ISO Invariance

ISO invariance. What is it? Since I’m just barely beginning to scratch the surface of the whole concept of ISO invariance, I don’t feel qualified to tell go into details as to what it is. To begin to get an understanding I recommend going here. In a nutshell, ISO invariance is the concept that the quality of today’s camera sensors are beginning to approach the point in which ISO is not as important as it once was. Basically, in many cameras, you can keep it at the base ISO, under expose, and then in post bump up the exposure or shadows as needed and you won’t take a hit with noise any more than had you used the “proper” ISO to begin with.

OK, so then why does this make ISO invariance something cool? There are a couple of reasons that come to my mind: Preserving highlights and selectively brightening photos in post to effectively increase dynamic range far beyond what your camera’s sensor can do on its own while still maintaining relative control over the noise that’s introduced which pushing shadows and/or exposure. Again, I’m far, far from being an expert in ISO invariance. Hell, at this point I’ve barely got a rudimentary understanding. I’d recommend checking out the link above for sure.

What I can do is show you an example of what I’m talking about. Keep in mind that my current camera, a Nikon D5200 is only somewhat ISO invariant. If you’d like to find out how ISO invariant your camera is, this is a good place to look at. Just go there and select your camera from the list on the right. The more level the line the more ISO invariant the camera is. For example, the Nikon D5200 is fairly ISO invariant; closely on par with the D610, not as much as the D7200, and it completely smokes the Canon EOS 5D Mark III. But the Mark III smokes it in native ISO performance for sure. But that’s another topic.

Way underexposed. ISO 100, 18mm, f22, 1/60 sec

Anyway, in this photo, it was taken substantially underexposed. -2EV to be precise. I’m not sure why I did that, but I did. It makes a good photo to test ISO invariance, though:
You can see that this photo is quite underexposed. For the sky it’s not so bad because those clouds are awesome and it’s nice to keep the details without blowing out the highlights. But, if you brought up the exposure to get the sky just right, you’re still going to be pretty off in the rest of the photo; especially the shadows. So, what I did with this in Lightroom was brought up the exposure by 1 stop. That was perfect for the sky and clouds. But the rest of the pic. To address that I used the Mask tool in Lightroom to selectively bump up the exposure of the foreground by another stop; painting it in. After that, I pushed the shadows a bit–actually quite a bit. +71. The highlights I pulled -70. I then tweaked the blacks and whites to just below the clipping level.

I then moved it over to Photoshop and did some color grading with curve adjustment layers, did some noise suppression with Dfine 2 and added some contrast and detail with Topaz Clarity because, well, clouds. All of this a pretty light though. There wasn’t much noise to contend with. I also brought down the global saturation a bit as well.

This is what I came up with:

There was a ton of detail hidden in those shadows that was completely recoverable. Granted, I’m dealing with the D5200. It ain’t no Sony ar7ii or Nikon D750, but for this little crop sensor entry level camera, it’s not bad at all.

One thing that I’ll point out, though, is that even with as little noise as there is here, I think that there would be even less had I exposed ETTR, peaking the highlights and bringing it down. Sort of an opposite approach. But I suspect that there is a real risk of clipping some highlights in the clouds to the point of not being recoverable. Whereas this approach has no risk of clipped highlights. The slight noise is an acceptable trade off in my opinion.

Cinematic Looking Photos

Cinematic looking photos that look as if they’re a still from an actual film are pretty cool. Kitschy? Yeah, a tad, but still cool.

If you’ve paid attention to movies you’ll notice that they seem to have a pretty unique color grading scheme; usually a kind of teal and orange pallette. In fact if you haven’t noticed it before, now that I’ve brought it to your attention, you’ll notice it enough to where it might drive you a little nuts. There are all kinds of ideas as to why films predominantly use a teal and orange color grading.

The ones that I think seem to make the most sense is that:

1) colors in the yellow/orange/red spectrum contrast nicely with colors that are in the blue/green spectrum. In my observation this is true. Complementary colors contrast nicely and add a vividness without hashing the saturation. You’ll notice that often times movies tend to be a bit desaturated yet still pop. I think it’s because of the use of complementary colors. I say often times; keep in mind that if you’re watching a Michael Bay flick, all bets are off. Everything, including the color grading seems to be turned up to 10. Anyway, human beings no matter their ethnicity tend to have skin that falls into that yellow/orange spectrum. The orange teal grading makes actors stand out.

2) this is, I think, a biggy. The orange and teal pallette tends to replicate so called golden hour lighting quite nicely and golden hour lighting pretty much rocks.

Here is a photo that I’ve sort of given the “cinematic” treatment.

Anna With A Rifle

Anna With A Rifle ISO 100, 35mm, f16, 1/125 sec

Granted, it’s not full on “cinematic” in that I’ve kept it a bit brighter than you might usually see. Actual movies tend to have the blacks and shadows crushed a bit more than my attempt. Also, perhaps the skin could have been just a touch more orange. The reason I chose this image is because I think it looks intriguing from the get-go. It looks like a slice of a bigger story; perfect for a faux movie still. By the way, this photo was taken using off camera flash; 300ws strobe camera left with a 22″ beauty dish.

For more information regarding giving your photos a full blown cinematic treatment I recommend first checking this tutorial out. It’s a great tutorial that even if you don’t want to do the cinematic thing it’s full of great information regarding curves and general color grading. Then, to add that extra cinema touch, this tutorial goes into adding the black bars to the image, and explains the aspect ratios of movies. I mean, if you’re going to go cinema, you may as well do it right.

Bonneville Salt Flats Photo Shoot Daylight Off Camera Flash

Bonneville Salt Flats Photo Shoot With Daylight Off Camera Flash

Girl In A Skirt At The Bonneville Salt Flats ISO: 100, 50mm, f16, 1/200 sec

I’ve dabbled in off camera flash for the better part of a year now and as I progress I can say that it’s completely changed how I approach photography; even when I don’t use flash, my way of thinking has completely changed. It has helped me to become more aware of light and how it affects a photo. Yeah, that seems almost rudimentary. Light is always important, but trust me, wrapping your head around off camera flash will reroute some synapses in your brain vis a vis lighting and it will be a good thing. Even when you think you don’t need to use flash (and yes, you may not NEED it) it’s beneficial.

In the photo above, taken at the Bonneville Salt Flats in Utah you can see that it certainly didn’t need flash, but it really added something to the shot. The sun was hitting the subject from behind at about a 35 degree angle. for the off camera flash I set up a 300ws strobe with just the 8″ reflector at camera right more or less perpendicular to the sun; just out of frame. In fact I had to clone some of the stand out. It helped immensely to lift the shadows under the hat and add a bit of a pop to the model overall. I’m happy with the shot.

My camera’s max sync speed is 1/200 second which makes it very difficult to bring down the ambient, hence the f16 aperture setting to help bring down the sky a little. Since I don’t have a neutral density filter or high speed sync capability my goal is a portrait/model/landscape shot because, well, I don’t have any choice. Since my DOF is miles deep I may as well incorporate the background into the shot. The Bonneville Salt Flats is perfect for that.

Eventually I do want to do some outdoor flash with shallow DOF so you can bet your sweet tukis that I’m going to invest in a neutral density filter. Also, I see a HSS setup in my not too distant future as well.