When you are starting into this hobby of shooting (not with the gun, but with a camera), it can be little intimidating with all those terms and definitions around. More often than not, I felt that I made a wrong choice of picking this for a hobby. As I spent more time playing with them, then it was pretty easy to comprehend and very interesting. When we friends get together we often talk about so many things on photography, but each one of us would have a different perspective on those terms. We more or less mean the same thing, but our approach has been quite different. So this is to encourage those who are hesistating to take photography. Don’t be intimidated by them. They are pretty easy to understand.
Photos capture moments and freeze them in time. Its interesting to see the science behind photography. In simple terms we are basically capturing the light reflected by an object and storing them in some format for freezing them in time. Since we are in a digital world, we use digital methods to achive that. Some movies show how photographs were shot in olden days. The Last Smurai comes to mind for an expample of that. They would have a rectangular shaped box, with a hole (aperture) and cap (shutter) covering it. The photographer would then at the appropriate moment, would open the cap for a period of time (shutter speed) and then would close it back. All he did was to expose the film inside the box to a reflected light source for a definite amount of time. This produces a negative image on the flim which would be then would be processed to produce a photograph.
As science advanced, so did the method of taking photographs and the skill associated with taking those shots. Today, with the hi-tech equipments available, its a lot easier to take photographs and the necessary skills needed to produce good quality photos can be learnt. The fun is in learning those skills and trying to produce good compositions.
Lets define some terms used in photography world. The definitions are not written in stone, but tend to be more or less the same. But as we gain more experience, our level of understanding of these terms changes. So I’m not going to be too bothered if I don’t get the meaning of a particular term. But this page, would sever me as reference whenever I want to re-visit the definition…more like a glossary.
Sensor/Film: This is the place where the reflection gets recorded. Film rolls were used in earlier days and digital censors are used now. Another thing to note out here is the sensitivity of the film (also known as speed). Today its more identified with the term ISO. Some brilliant people quantified the sensitivity of the sensor/flim and gave it a number. So you’ll see values of 100, 200, 250 etc which denotes the sensitivity of the sensor/flim. An ISO setting of 200 is more sensitive towards light than with a value of 100. So if you are in a very dark environment and want to still capture the details in your picture, then one way to do is to bump up the value of ISO in the camera. Of course there are other things you’ll have to consider when you do that…but lets reserve that discussion for a later date.
Lenses: People of have written books on explaining just lenses used in a dSLR. So if you have to define this, then its easier to read it here. Its the thing which helps us to see the object/subject we want to photograph and gets attached to the camera body of dSLRs. Most advanced point and shoot cameras have a fixed lens attached, so you won’t have an option to change them. In SLRs you have so many choices of lens; prime, zoom, macro, wide-angle etc. The amount of $$ that you are willing to spend would be the limiting factor here.
Aperture: This is the size of the opening in the lens which controls the amount of light entering the camera. The allowed light then falls on the sensor to record an image. In the example used at the starting of this post, this would be the size of the hole in the box. If the size of the hole is big, then more light is allowed to enter the camera and if its less, then less amount of light is allowed to enter.
A more scientific definiton of it would be that an aperture denotes the diameter of the opening (hole) in lens and is calculated by dividing the focal length (f) of the lense by a stop number. Aperture is represented by f-stop number. Eg: f:1.8, f:2.5, f:3 etc or simply numbers like 1.8, 2.5, 3 etc with each unit either increases or decreases the size of the aperture. All these number just represent how big or small the hole is going to be.
This is where we get confused when we are new to these terms. Consider this: The smaller f-stop the bigger the hole is. If you are a math oriented person, then you shouldn’t be confused with that statement as you would go the math way by dividing the focal lenght with the stop number and then say…’yes that makes sense’.
But for someone like me who hates math, we would assume that f:1.8 setting in our camera will make the hole smaller than f:2.5. Conversly f:2.5 value will make the hole bigger. But in reality its exactly the opposite; f:1.8 makes the hole bigger and f:2.5 makes the hole smaller.
Seasoned hobbists would say…”oh! just stop down the aperture by 1 stop and you’ll get the exposure right”. While trying to follow that suggestion, I look at my camera and if the current setting is f:5, should I set it to f:4.5 or set it to f:5.6. What do they mean by stop down?
In aperture values, they are suggesting me to go from f:4.5 to f:5.6 as that stops down the amount of light entering the camera by decreasing the aperture. Each stop value either increases or decreases the amount of light by half. So if I go from f:5.6 to f:4.5, then I’ve doubled the amount of light entering the camera. Cameras now allow that to be controlled in 1/3 values to give users more control over their exposures.
If you are still confused, then follow what I did; just take their word for it 🙂 To make it easy for me, I repeatedly kept saying the following statements:
f:4 is larger than f:5.6
f:4 makes the hole wider than f:5.6
f:4 allows more light than f:5.6
f:4 to f:5.6 means a stop down
f:5.6 to f:4 means a stop up
Evenutally you’ll get a hang of it and use them like a seasoned hobbist 😉
Shutter Speed: The speed of the shutter determines the amount of time the light is allowed to fall on the sensor. It is denoted by 1/nth of a second. Going by our original example of the rectugular box, it’ll be the amount of time the photographer keeps the cap open. So a shutter speed of 1/250 (or simply represented as 250) would allow the light to hit the sensor for 0.004 of a second. Again mordern cameras allow you to change this in 1/3 stops like: 1/500, 1/400, 1/320, 1/250 etc. What value you choose for shutter speed also has a profound effect on the exposures. You can get crisp shot of a batsman hitting a cover drive freezing everything OR you can introduce some blurness in the shot to denote motion. For now I just remember it as slow shutter speeds (1/250 is slower than 1/500) is to get motion blur and faster shutter speed (1/500 is faster than 1/250) is to freeze the action.
Exposure: This term is used to mean multiple things and you’ll have to look at the context of its usage. It can mean a picture as in “You have got a nice exposure dude!” or denote the slowness in shutter speed as “You need a long exposure to get that shot”. More often than not, it just means a picture. Again as you spend more time in reading stuff, you’ll gain more understanding of its usage. For now I’ll just mean its a picture 🙂
White Balance: This setting helps in ensuring the color we see through our eyes is the one recorded by the sensor too (or atleast very close to it). How often to you see a color and ask “Whats the temperature of that color?” If you are a physicist then you may think on those lines, but for others we wouldn’t care what temperature it is. The human eye has got a wonderful lens which takes care of adjusting the color temperature for us. So we see colors which we have built-up in our database through our growing years. When you look at a white paper under a tungsten bulb, you’ll associate a yellowish tinge to it, but the same paper when looked in sunlight would look more white. This association of correction is done automatically for us. But in cameras, we have to take do it manually (most of the cameras also do a good job at the correction autmatically). So you’ll see some presets defined in the camera like daylinght, sunlight, shade, cloudy etc. Almost all of the dSLRs have an option to explicitly specify the color temperature so that you can get more desired or natural looking exposures.
There is so much more to add to this list, but I’m too tired right now to type anything more. The three key things; ISO, Aperture and Shutter speed is more than enough to get started. You don’t need to have a high-end dSLR to play with these things. Most of the point-and-shoot cameras also provide them. So take out your camera, look for Aperture, ISO, shutter-speed and start having fun!