Images from the Id: Or do I need a new title?

Award winner from the Albuquerque Aquarium

During this last week, I have been doing some research. The term id may or may not fit for this blog. Originally, my thinking came from a line in one the greatest “real” Science Fiction films ever made, Forbidden Planet (1956). Dr Morbius (Walter Pidgeon) lay dying after his subconscious, with the help of the Krell machines, created a perfectly horrible monster. In a final  line (delivered to Commander Adams-a young Leslie Nielsen), realizing his place in the massacre, he calls them “Monsters from the Id” The term seems to have a very negative connotation of monsters, unrepressed urges and uncontrolled results. This is not really what I expect for you to find here. You should learn control not chaos. So I’ll keep the name with that understanding just because I like it.

So what about equipment? It is actually very easy, the equipment you use should match your vision and how much control you need of your image. Enough? Well, maybe not. Let’s look at what you need to know and what you want to do and how that affects your choice of camera.

Light, light, light – that is what it is all about. How do you control the light? Think of a triangle. There are three point on the triangle and there are three things you must always be aware of when interpreting what is called exposure. Some of you may know this but bear with me, you may learn something new.

The first point is the ISO (in the old days it was called ASA). The ISO represents the setting of how fast the sensor collects light. Traditionally, not too modern, below 100 was considered SLOW and over 400 was FAST. Now we use the terms LOW and HIGH. High lets you take images in, surprisingly, low light. But it has a draw back. When a high ISO is used certain problems are caused by, for lack, of a better explanation, the BIG Bang and how the physics of the Universe work. This is called noise and it shows up as dotting of the image, decreasing sharpness (subject for the future). Many modern cameras do a good job improving the noise. (another future subject). Remember this, doubling the ISO doubles the amount of light collected and halving it halves the amount of light.

Second point of the triangle is the shutter speed. This is expressed in fractions of a second. It is the easiest to understand. Remember, if the shutter speed is doubled the amount of light is doubled and vise-versa, so 1/250 gets twice as much light as 1/500.

Third point is aperture or better called f-stop. This one can be confusing, f-stop is actually a ratio of the lens opening (aperture ;-)) and the focal length of the lens. Because it is a ratio, the f-stop such as f-16 should correctly be expressed as 1/16. What does that mean? Well, if the f-stop number doubles the amount of light is halved, it is a ratio. So f-16 is twice as fast as f-32. Remember that.

This all means that the three are interlinked by their nature. Let’s say, you have a correct exposure for a scene of ISO-100, Shutter Speed 1/250 and an Aperture (f-stop) of f-8, but your subject is moving and the shutter speed is too slow, you need 1/500. Since you have doubled the shutter speed (half the light) then you must double one of the others to keep the same exposure. Aperture to f-4, remember smaller means more here, OR (not both) double the ISO to 200. This is the way to keep that exposure.

So what do you need to control the light? An adjustable camera. Pros and advanced amateurs want  controls on-camera and we pay for it. We require fast and easy adjustment for each. Consumer level adjustable cameras, in most cases, require going through various menus to make the adjustments. This is a pain and awkward but the only choice for many cameras. Either way, learn your system and practice it. If you buy a new  camera consider on the body easy controls, usually worth the extra cost. This is the weakness of point and shoot and smart phone cameras, most have little or no control of exposure. Phew, got that out of the way.

Automated processing is another problem and another subject.

Next Week – A Little Planing Goes a Long Way