Tools for Drawing with Light

Ah yes, the tools of drawing with light, or in simpler terms, cameras.

As some of you might know, cameras and photography are my newfound passions, and as a result, in the recent few months, I have done a good amount of web-scanning on cameras. While that reading has been primarily on Digital SLR cameras and their lenses, in this first post I should perhaps refrain from going into that specialized topic. SLR's, Digital SLR's and Lenses will be the subject of future posts on this blog, so will be photography. But as of now, lets deal with cameras.

Well, for some, a camera is used to turn moments into permanent memories (well, as permanent as this universe allows), and for some, it is the brush to paint on a chemical canvas. And technically, a camera is a device to capture and reproduce some visible part of the universe, whatever it may be.

These days, there are primarily two types of cameras available. The ones that use chemical based film to capture the images, and these have been around for more than a century and a half now, and the ones that use a digital sensor. The second type have been gaining in popularity over the last decade, and their numbers are snowballing now.

If I start to discuss the chemical film and digital sensors now, it will be ages before I will be able to get back to the topic that I am actually writing on, so I will for now get back to what the rest of the camera needs to do, and will take up these two things sometime else.

While over the ages, there have been countless new features and technologies added to cameras, the basic principle, as with perhaps all things has remained the same. A closed box with an opening or a lens at one end to allow light to enter and create a image. (And use that film or sensor to capture this image).

The type of camera that has only a small opening at one end and no lens is referred to as a pin-hole camera. The light simply passes through the small hole and forms an inverted image on the back surface of the (almost always) cubical box that is the pin-hole camera.

For the camera that have them, the lenses take upon the job of creating an inverted image of the scene in-front inside the camera. One important thing to note here is that each lens has an focal length and this focal length is the distance behind the lens where the image (of objects at infinity) is formed inside the camera. The film or the sensor needs to be placed here to get a sharp and defined image. For objects that are closer than infinity, the distance between the lens and the image plane (the place where the image forms and the film/sensor is placed) needs to be altered. And this process is called "focusing". On modern cameras with modern lenses, that actually are complex devices themselves with multiple pieces of glass that can move to focus, and on zoom lenses, even vary the focal length so that the field of view whose image is formed and captured differs, this process no longer requires the actual lens to be moved - just one or more glass piece of it. And the focusing now on most cameras is done automatically - using distance sensors and servo-motors and what not. Focusing speeds faster than that of the human eye have been achieved in professional lenses, and it can only go faster and more accurate than ever before.

Well, lets get back from that focusing detour and continue with the camera. If the light always fell on the film/sensor, it would actually create nothing but a totally white image. Thus, the amount of light that falls on the film/sensor needs to be controlled, so that a photograph that looks usable and good is formed. To do this, there are quite a few mechanisms available on the camera and also a lot of assisting aids.

The first and foremost of these things is the shutter. As the name suggests it is an object used to "shut" out the light. It allows the light from outside to enter the camera for a fixed duration that is usually a fraction of a second.

Another way of controlling the amount of light is the size of the opening at the front of the camera. It is called the aperture and is usually defined by the aperture number of the f-number, which is the ratio of the focal length to the aperture diameter. Some simple geometrical maths says that for a fixed f-number, any focal length would require the same amount of shutter open time for the same exposure, provided that the ambient light intensity remains the same. And this is why the f-number is a very important parameter. The catch here is that the smaller the aperture number is, the more is the light that passes through (it is inverse square root ratio) and smaller is the shutter time that can be used(faster movement of shutter), thus giving the name to large aperture(small aperture number) lenses of "fast lenses".

There is another way of allowing the shutter speed to be slower or faster, but that is to do with film types and sensor sensitivities so we'll deal with it some other day.

To guess the combination of aperture size and shutter speed to get a good exposure is not something everyone can do, and this is how we reach at what even the "pros" - who often say that the camera is the least important thing required for taking a photograph - say is a most crucial thing - the "meter". Short for light meter, this (now) tiny device measures the light intensity and suggests the shutter speed for a set aperture - or vice-versa. Modern meters are TTL - through the lens - judging the amount of light coming from the actual scene that you are going to photograph and thus more accurate, and are now usually linked electronically to the camera's automated shutter speed and aperture setting systems to give you a point and shoot system - no need of fiddling with the settings to get a good shot. There are a lot many new jargon-words attached with the metering systems of these days, that if used properly provide good tools to utilize the camera that bit more effectively.

Another very important thing that I almost missed out telling about is the viewfinder. What good is a camera if you cannot estimate what it is going to photograph? The viewfinder is that which lets you see the thing that the camera is supposed to be seeing - and in case of TTL viewfinders - what it is actually seeing, to help frame your shot. The non-TTL viewfinders have a parallax error that gets pronounced with closer objects being photographed, and thus are not the ideal solution. The TTL viewfinders are harder (read costlier) to achieve, and while traditionally are found only on costlier SLRs (Single Lens Reflex) cameras (we'll discuss these in good detail some other day, don't worry), these days electronic TTL viewfinders and screens are very popular on the digital cameras. It is an optical TTL viewfinder still that is elusive, because it is the best.

There are other things like the film advance system (for the film-roll cameras) - both manual and automatic, some sort of displays to show what the camera is going to do the next time you press the shutter, some buttons for direct functions etc. etc. On modern digital cameras, there are increasingly larger color LCD display screens that show the images, menus for settings, previews, and also lots of buttons to navigate the menus and set the settings.

Well I guess for today this is a good thing to read about cameras, and I guess I will be writing a LOT more about cameras, types of cameras, lenses, digital camera technology, photographic films, photography and camera jargon, camera and film formats, silver halide, megapixels, depth of field, bokeh, primes, zooms, superzooms, point-and-shoots, full-frames, rangefinders, 35mm...

The list goes on, and so do writing opportunities, and someday I hope to have written enough about cameras and stuff that I have no more to say.