Exposure Basics, lesson three?

Started Mar 18, 2013 | Discussions thread
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Najinsky Veteran Member • Posts: 4,931
Re: All at once or nothing at all?

Perhaps you are too smart to understand the simplicity of the use of the exposure triangle. It happens.

Or maybe I hadn't heard of the exposure triangle until a few years ago, and I was very much into photographic literature and took quite a number of courses when I was in my early and mid-teens. Somehow myself and a whole generation around me coped just fine without it, and a whole generation of teachers also thought that they didn't need it.

If somebody needs a triangle to understand how many railway carriages it takes to transport a given amount of, eg, coal, with the length and height of the carriages as variables, they didn't advance much beyond elementary school.

I'm sticking to my opinion that the triangle is mainly a way to show something fancy, so the students say aah and ooh. Nobody ever users the triangle to actually calculate something except maybe as a forced exercise in class.

I explain that there are two fundamental controls we have understand, the Aperture and the shutter speed, and also a camera setting that it helps to have an understanding of, especially if they like taking photos at night but find the shots turn out like crãp.

Then I show the exposure triangle.

You show them the triangle before you have explained them what ISO is? How could they understand anything of it they don't know what ISO is?

That's the point of the triangle (nearly the whole point actually).

The basic point with beginners, in everything not just photography, is that you don't yet know what you don't know.

It's a pretty standard approach in lecturing:

Tell them what you're going to tell them (what they don't yet know).

Tell them it (the main presentation).

Tell them what you told told them (the recap).

The exposure triangle is a simple graphic used for the first step, tell them what you're going to tell them, by definition, what they don't yet know.

Then I come back to digital and talk about the sensor. I explain that it's sensitivity to light doesn't change as was the case with different film speeds, but it tries to simulate this by boosting the recording to make it look like there was more light captured than there really was, to prevent the image from looking under-exposed.

That and your next paragraph is actually a pretty good explanation that avoids that misleading statement that changing the ISO changes the sensitivity and noise of the sensor. But wouldn't it make sense to add at this point that one can do in principle exactly the same thing on a computer: boost the recording?

It's a beginners course. There was no assumption/requirement they use a computer to post process their images (at the colleges stipulation). Some of them (are you reading Mary?) even had all their photos stored on the card in their camera and went into Jessops to print them and buy a new card once they'd filled the old one!! This came to light when she explained why she only bougtt small capacity SD cards, because it took too long to print from the big ones with too many images on.

This is one of the reasons ISO has to be incorporated because they are paying to learn how to get a good picture when they click the shutter. And also to understand their camera controls. When they shoot in auto, which most do at the start, the camera sets Av Tv and ISO, so it is part of the syllabus and part of what they are paying for to have those explained and be able to control them themselves.

However, there was a section of the course (it's an 11 week night-class course with each class lasting 90 minutes+ on Wednesday evenings) that introduced computer based workflow for backup, storage, albums, slide shows, uploading to Facebook/MySpace/Flickr, book printing services etc.

This included a basic introduction to post processing for crop, straighten, red-eye and simple colour adjustments. This was the section that required the most latitude as there could be huge variance in existing experience among the group. Those of the group who were up for it could stay behind after class and I would introduce the concept of raw files and this would include discussing sensors in more detail in context of noise, exposure latitude and white balance.

This was over three years ago before I went travelling and I think the balance was about right. If I were revising the course today, I would try to extend this area. However, more advanced post processing was covered in the more advanced intermediary course.

Third, I'm hoping to help those more technical minded people understand the intentions and the role of the exposure triangle.

Let me ask you my key question again in a twofold manner: (1) What would you students answer at that point what 'exposure' is? And how the exposure triangle describes exposure? (2) And what would be your answer if the students asked you?.

I wouldn't ask them at this point. At this point the aim is to overcome their fear of the buttons on the camera. Their fear of pressing the wrong buttons on the camera and 'breaking it', meaning making the camera start making cr@p pictures on every shot.

The goal here is to get them comfortable with the notion that there are three major settings that are controlling what their photo will look like when they release the shutter. Here we are merely introducing those terms in an overview. Exposure is given a glancing exposure in this overview but it isn't the goal at this point. Following the introduction, Aperture and Shutter speed get sections of the course all to themselves which includes technical, practical and creative aspects. ISO is only mentioned in passing in context of noise, running out of light and reading the meter, so the elevated role of exposure is already inherent in the course structure.

But it isn't until after the section on metering and exposure compensation that the practical definition of exposure has been fully covered in sufficient detail to ask more (basic) technical questions. But even then, technical definitions are not the emphasis of the course. The emphasis is always that photography is fun, and it's a lot more fun when you enjoy looking at and sharing your photos afterwards.

Understanding the controls is initially a hurdle to be overcome, but once mastered they become and opportunity to express our creativity and capture our visions, or just get some nice snaps of aunty Joan's 4th wedding, or their sons graduation, whatever they're looking for. There is a huge amount of practical work in the course. After the basic intros to the controls, the course would meet outside while there was still enough light for some practical assignments, then move into the class to review and discuss, then onto the next lecture part.

I explained that after week two when the controls are understood and practiced a little, even if my plane crashed (I was sometimes working on a different Island and had to fly back to give the course) and I died, they would still be able to to learn and enjoy the course, simply by all meeting up and experimenting and devoting some time to playing and practicing, their photography and enjoyment would grow. Photography is a hobby that rewards practice and participation.

By the end of the course they would know that Light Exposure is the amount of light falling on the recording surface controlled by the Aperture and Shutter Speed and that ISO is a setting that controls how the camera processes that light into their image. They would understand that the sufficiency of light can be measured with the meter and that the meter can be made to meter the subject or the whole scene and what the consequences of that would be for different types of scenes and subjects. They would understand the meter can be overridden with exposure compensation, and that the metering includes the impact of the selected ISO when displaying exposure values. They would therefore understand that the exposure triangle fully explains what their meter is showing them.

I would answer whatever question was asked with whatever level response was appropriate at that time. What is exposure? It is a central term around which photograph is based. Photography is the exposing of light onto a recording surface to capture the scene from a moment in time. Exposure is a term that is commonly used for various elements of that process. It's both the technical definition of the amount of light, as in the amount of exposure, which has some scientific terms to describe it, and also the actual act or instance of exposing, and it can be the term that describes the result of of having been exposed, like a single exposure or double exposure on a roll of film.

How the exposure triangle describes exposure? The exposure triangle does't attempt to describe exposure, it attempts to illustrate the three settings that control how the photo will be captured. The exposure amount is represented by the Aperture and shutter speed, while the ISO represents how the light will be used to record the image. Together they comprise what the camera's meter tells you about the scene before you attempt to capture it.

Presenting a single graphic with only three elements is a comfort to a beginner because it helps convey confidence that it's not as complex as they may have feared.

I think your faucet example is much easier to understand than a triangle, people have to learn how to read such a triangle, but everybody intuitively knows how a faucet works.

And in general, I am not sure whether teaching the basics of photography without the basics of image adjustment is the proper approach these days.

Image adjustment, both in camera and on a computer is part of the course, just not part of the introduction.


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