Photography 101 - Lesson 2
Let me start by saying that I’m no expert. There are tons of people on TravelBlog.org, and in the world for that matter, that have a better understanding of photography than I do. What I impart below has been learned mostly through hours of research and actual photography while traveling the world. I have, since I learned most of this, taken classes but found them to be pedantic and pretty much useless.
If you feel that parts of my lesson are wrong or could be better, feel free to add comments in the forum below. Also, please ask questions. There is no such thing as a stupid question, period!!
Learning how better to use aperture changed my photography forever. In my opinion learning and experimenting with aperture is the number one thing an amateur photographer can do to improve his or her craft. With that said, explaining aperture may be one of the more difficult things for an instructor to do so bare with me
As I pointed out in the last lesson ( Photography 101 - Lesson 1
) the aperture is similar to the pupil of your eye in that it gets bigger or smaller dependent on the light needed to get the best picture. Aperture isn’t the only deciding factor in whether or not your picture is exposed properly, but it definitely plays a big part.
In most cameras there is an automatic mode that makes most of your decisions for you when it comes to the technical aspects of taking a picture. As you point your camera at an object and press the shutter button, the camera decides the right aperture and shutter speed to get the best picture for the given conditions. There are limitations to these calculations though which makes it better for you, the photographer, to be able to make the decisions yourself in order to get the picture you see in your head.
The first step to taking control is using aperture mode on your camera, if your camera has one. On Nikon cameras this setting is referred to as A
mode (or aperture priority) while in Canon cameras it is referred to as Ap
mode which is also referred to at aperture priority mode. Both of these modes allow the user to select the aperture while the camera sets the subsequent shutter speed to match the aperture selected. This mode is like stepping half way between automatic and manual. You set half the equation instead of letting the camera decide it for you.
So, What Does Aperture Do For Me?
Have you ever noticed that you can see further distances clearly during the day than you can at night? There’s a reason that in dark conditions your vision isn’t as clear as it is during the day and that reason is aperture. During the day, especially in bright conditions, your pupil gets really small giving you, effectively a small aperture. With a small aperture more of the scene in front of you is in focus. While at night your eye has to open up wide in order to let more light inside your eye. With your pupil open wide you can’t see as far or have as much of a scene in focus. This concept is known as Depth of Field
As the aperture in your eye, and subsequently in your camera, gets smaller so does the depth of field. This means that with a really small aperture more of your scene is in focus. When I say more of the scene is in focus I mean more of it front to back is in focus. For instance, have you ever seen wildlife photography with a cool blurry background? That was taken with a wide aperture which has a very shallow depth of field, meaning one thing is in focus and everything in front or behind it is slightly out of focus. On the other hand landscape photography, where much of the scene even far away from the focal point(place you are focusing on), is still in focus. This type of photography is usually taken with a small aperture which gives a larger depth of field. Make sense?
This photo was taken at a wide open aperture which creates a shallow depth of field. Note how the background is blurry and even some of the grass in front of the spider web is blurry too.
This photo was taken with a small aperture. Notice that the distance is in focus and also the items in the foreground are in focus as well.
You are starting to see why aperture is important for the type of picture you are trying to take and why you would want to make these decisions yourself. But the discussion goes even further. Most of the time, the camera tries to set your aperture in the middle (not to small, not too big) in order to get a good clear picture but sometimes that can cause problems. In all situations the smaller your aperture, the longer the camera must open the shutter to get a correct exposure. This isn’t a big deal on a bright sunny day, but inside a cathedral this can be a huge problem. If the camera sets a small aperture and a long shutter speed, it is nearly impossible for a clear picture to be taken while hand holding the camera because you can’t hold it still long enough for the picture to take. So, you might want to drop the aperture which will shorten the shutter speed and make it easier to get the picture. Sure, more of the picture will be out of focus due to a smaller depth of field but at least some of it will be in focus because the shutter speed is short enough to capture the picture clearly.
Understanding the Terminology
People are often very confused by aperture terminology because it doesn’t make sense unless you understand all the math behind a camera. Lets try to make it simple and see if we can make it a bit easier.
Apertures are referred to in f-stops, for example f/8 or f/22. These numbers refer to a ratio between focal length (often referred to as zoom, 50mm or 200mm are focal lengths) and aperture size. Thus the f-stop is a ratio or fraction. Understanding that these numbers/symbols are fractions helps you to understand the relationship between aperture and the symbols themselves. Enough of the complicated stuff, lets make it practical
The bigger the bottom number the smaller the aperture. Sounds confusing, but it doesn’t have to be. Remember that f/22, f/8, or f/1.4 are fractions and therefore the bigger the bottom number the smaller the actual number is. Everyone knows that ½ is bigger than 1/8 which exactly like aperture numbers. Common apertures range from f/3.5 to f/22. At f/3.5 the lens is wide open letting as much light in as possible, while at f/22 the aperture is very small letting in very little light. These numbers are right on the camera itself, allowing you to select the perfect aperture by selecting the f-stop.
Now, it is important to understand that aperture settings differ between cameras and lenses if you use a DSLR. For instance I own a Nikon 18-200mm lens which allows me to go from really wide angles to a really far zoom. This camera can only open the aperture up to f/3.5. That’s pretty wide open for outside photography but inside I need pretty good light to get a good photo. On the other hand, Nikon makes a lens that is a 50mm non-zoom variety that can open up to f/1.4. This lens lets in more than three times the light at its widest aperture than my 18-200mm f/3.5. Of course, in order to let that much light in the lens has a wide aperture and an extremely shallow depth of field, so shallow that you nose might be in focus while your eyes are starting to get blurry. That can make it really important to pick your focus point wisely!!
Standard aperture is usually between f/8 and f/11. A saying used by photo journalists is “f/8 and be there.” This refers to the fact that f/8 allows you enough depth of field that you don’t really need to think about it and instead you can focus on being in the right place, at the right time, taking the right picture. If you are walking through the streets of Morocco looking to get people photo’s f/8 is a great place to be, or at least to start from
This pic was captured from the hip with my camera set to aperture priority mode with the aperture at f/8.
What is this crazy ISO thingy?
While this is a pretty long lesson, I will continue since our fearless leader Ali has directly requested that I talk about this particular topic. What is do ISO ratings mean and how can they help me out.
The history of ISO ratings is pretty complicated but for today’s digital photographer it is, thankfully, a bit more simple. But first lets give you some background so that, if nothing else, you can wow your friends at dinner parties.
Back in the day if film there was a bit of a conundrum about how to standardize film emulsions so that photographers would know how to set their shots up for the type of film they had in their cameras. At this point the International Standards organization
, e.g. ISO, stepped in to help standardize the film types. Standards were set and they have stuck with us into the digital world. Strangely these standards work just the same for image processing in the digital world as they did in the film world.
In the simplest form the ISO number refers to how long it takes for a piece of film to expose properly. The higher the ISO number the less time it takes for the film to expose right. This can be really handy in situations where you can’t predict the lighting conditions. For instance, most cameras today start their ISO rating at 100 (some pro models go down to ISO 50) but if you turn your camera up to ISO 400 then the film or processor exposes quicker and thus you can get a picture that is clear even in lower lighting conditions.
Shot at ISO 1600 it was still blurry due to long shutter speed but I could never have captured this at ISO 100.
There is a catch to all of this though. The higher your ISO rating the more noise
you add to the picture. In some cases this noise shows up as a grainy picture but it can even go so far as to create a weird off color haze that really screws up your pictures. Because of this noise most photographers try to keep their ISO as low as possible. During a sunny day mine gets set at ISO 100 and stays there. But, recently I was in a rodeo that was pretty dark, in order to get a good picture I had to turn my ISO up to 3200 which, as you can guess, is very, very grainy. Its almost unusable for a printed photo but was fine for my blog.
To be more technical, as ISO goes up it is the equivalent of shortening your shutter speed. When you go from ISO 100 to ISO 200 it has the equivalent of shortening your shutter speed by one stop or, in terms of aperture, it opens up the aperture by one full f-stop (it doesn’t change your depth of field but has the effect of letting more light onto the film). The scale goes like this:
ISO Number Number of Stops Changed
ISO 50 = +1
ISO 100 = 0
ISO 200 = -1
ISO 400 = -2
ISO 800 = -3
ISO 1600 = -4
ISO 3200 = -5
ISO 6400 = -6
Most point and shoot (non-DSLR cameras) go from ISO 100 to ISO 400. Decent DSLRs like my Nikon D80 tend to go from ISO 100 to ISO 3200. The incredible pro DSLRs go all the way to ISO 6400. Also, as you go up the camera price range the mid level ISO ratings become more useable. My camera is pretty useless above ISO 800 but ISO 1600 is pretty decent on my best friends Canon MarkII.
When in doubt turn the ISO up if you think that’s the only way you’ll get the picture you want. But, in the long run you will want to do you best to turn the ISO rating down so that you get good clear pictures. If you don’t have a tripod and want a night picture of the Charles Bridge in Prague then turn up the ISO but you will be much happier with a picture taking t ISO 100 on a tripod.
Taken at ISO 100 and an aperture of f/11 using a Gitzo tripod. Very pretty, no?
Well, that’s a lot of info to digest. I will try my best to keep these shorter in the future. Please ask questions, I’m sure I’ve forgotten some stuff.