Exposure Basics, lesson three?

Started Mar 18, 2013 | Discussions thread
bobn2
Forum ProPosts: 28,048
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Re: Quick correction.
In reply to Najinsky, Mar 21, 2013

Myself, I tend to think that the correct understanding is the more simple understanding:

  • Exposure is the density of light falling on the sensor.
  • Wider aperture and/or longer shutter speed means more exposure.
  • Greater exposure, larger sensor, and/or more efficient sensor means more light recorded.
  • More light recorded means less noise.
  • Sensors can absorb only so much light, beyond which you will get blown highlights.
  • Camera's ISO setting adjusts the brightness of the LCD playback and/or OOC jpg, as well as influencing the camera's choice of f-ratio, shutter speed, and/or flash power depending on the AE (auto exposure) mode you are using.
  • Image files have a limited bit-depth, so increasing the ISO may push portions of the photo outside the range of the image file, resulting in blown highlights.

Is it really that confusing?

Try it. Offer your services to a local college. Put the course together and get it approved by the college. Get them to include the course in their night class program, see if people want to sign-up and pay money for it. And if it all goes ahead, deliver the course and get a critique about how well the course was received.

It's really great fun, you meet interesting people, and it's one way to know for sure.

As it happens, I have some experience putting courses together and having them approved by colleges. I also have experience approving and accrediting courses put forward by others. Moreover I have put on photography courses for photography clubs and others. Not 'approved', but great fun, as you say.

But to give some partial answer. I believe if I submitted a beginners course with terms/equations like Total Light Collected = Exposure x Effective Sensor Area x Quantum Efficiency, the course would be rejected as having missed the brief that it is aimed at complete beginners.

There you get bemused by the vocabulary. I suspect that it is that 'Q' word, which makes people think of deep Physics. It's a perfectly simple concept, so many photons hit a sensor, how many get counted.

I'm a little different than many in that I have some experiences that are not at all common. I was the advanced programming course designer for Hoskyns. I was also the chief trouble-shooter consultant, meaning my name was listed in the experts directory, known as the "Oh shlt, who we gonna call, guide" (it was the post Ghost Busters era). That would be me. I solved issues with IBM Systems that IBM had failed to solved, "dam, who we gonna call now?". I was called on to out-geek the geeks who were hiding stuff from their bosses. I was the sole representative of the UK (in my specific field) invited by IBM to attend their technical seminars at their labs in Italy. One each from certain European countries, two from America and one from Canada. A small group the IBMer insisted on calling the elite.

I don't say this to brag or elevate myself, I say it because I want you to understand, I can do techie. I was, in that career, the techie's techie. However, I am somewhat different because I can also do beginner and this isn't all that common. The intro lecturers didn't have the knowledge for the advanced courses, while the advanced lecturers didn't have the patience or dumbed down (simplified, being more polite) vocabulary to keep the beginners on track. They would sometimes try if the scheduled lecturer was off sick, but it would more likely lead to 'brain-dump' tactics and end in tears. Yes, both delegates and lecturers do end up crying when faced with a group situation that overwhelms them into feeling they can't cope.

I think the teaching of programming is a really good example of how things go wrong if you Bowdlerise the essential theory in order to make it more 'accessible'. Essentially, you turn out people with qualifications but no ability, and end up with software products of the quality we have today - software is about the only field of commerce where you can get away with selling fundamentally dysfunctional products year after year, because everyone thinks that how it needs to be. It doesn't need to be like that, it just is because the majority of programmers aren't very good at programming.

An insurance company client ran an annual program taking six virgins; people with a degree in anything other than computer sciences. If could be Business Administration, Medicine, Legal, Drama, Languages, Photography and Media, whatever, just so long as it wasn't Computer Sciences. These would then be trained to become computer programmers, by me, in a 6 week intensive course (30 full days) over an eight week period.

Their rationale was that Computer Science Geeks were in general, geeks, and didn't make particularly useful additions to the business, lacking both business and communications skills. Dismissive, aloof and intolerant. More likely to hold the business to ransom than help drive it forward.

As an honorary computer science geek I was naturally a little skeptical, but we ran it for three years before the recession hit and they stopped the new hires. It was hugely successful.

My experience is that the people with no prior knowledge of programming are the easiest to teach, because they haven't adopted the unstructured and theoretically incorrect (and theory is important to understanding what is happening) mental models which block them really understanding what they are doing. Getting a dyed in the wool Basic, Fortran or Cobol programmer to write good code is very, very hard. With a blank page to write on, you can get established a conceptual framework that allows people to move forward.

The point of all this rambling is, teaching beginners is a lot more than just having the knowledge they lack. You need empathy and imagination to put yourself into their position, to understand where they struggle. A little psychology to figure out a way to help them over their hurdles. You need to pace the learning so people don't get bored while others struggle. And the biggest mistake the more techie lecturers make in this situation is in believing it is easy. Some even make the mistake of saying it in just the wrong way, directly at someone who is struggling, in the innocent hope it will help. Might as well just light the blue touch-paper.

I think you need the two things, firs the empathy and imagination that you talk about, and also deep subject expertise, in order to understand ho you construct a framework which allows the subject to develop. I've spent too much time with people struggling to unlearn stuff which they got from poor teachers and poor coursed, and too much time trying to sort out teachers who don't know as much as they imagine themselves to to characterise this issue as you do. I think this is simply a case (in general, without fingering individuals) of those who don't know, but imagine themselves to be experts, defending their right to pass on their ignorance to others.

So what do you think, are techies dismissive, aloof and intolerant? Seen any evidence of it here in the m43 forums?

Of course, some techies are, others aren't. The real 'dismissive, aloof and intolerant' attitude is 'I don't know this, so there is no reason any beginner should need to'.

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Bob

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