Aperture?

Another crucial element in photography, and except for the way it is written down, it is a rather simple concept. Aperture refers to the size of the opening in the lens that is letting the light into the sensor. That's pretty much it. The size of the lens opening. The hole. It has a lot of implications and a great impact on the resulting photograph, but it is still just referring to the size of the opening used to let the light in.

As you might expect, the larger the opening, the more light it lets in. So why would we not always use the largest aperture available and get the most light? Well, there are several reasons, but one obvious one should be that sometimes there is too much light. Outside on a bright sunny day, you may not be able to shoot with a wide open aperture without over exposing your photos. But the amount of light it lets in is not the only thing to consider. The aperture you choose also has a profound effect on the Depth of Field(DOF). And the larger the opening, the shallower/smaller the Depth of Field. This is important for many reasons, as depth of field is crucial to creating desired effects, such as the creamy blurred backgrounds(also called bokeh) many people love. And on the opposite end, you sometimes want everything(or as much as possible) in sharp focus, such as in a landscape photographs. So depending on what you're trying to do, aperture is probably going to play an important part in it. 


Here is a little demo I put together to demonstrate the effect of aperture on DOF(Depth of Field, the section of the image that is in sharp focus).

 
A few guidelines on aperture:

- For bokeh(that creamy blurred background), which helps isolate the subject(great for portraits!), you will want to use a wide aperture, and get up close, so shooting either wide open, or only slightly stepped down should help achieve this. There is a trade off in sharpness when shooting wide open, but it is mostly around the edges, and unless you are planning on making really large prints, it won't really matter all that much. But that's something that is easy to test for yourself and compare the results. Shooting at longer focal lengths helps with this too, so that's another way to get bokeh. Since at wide/large apertures, the DOF is shallow,  you will need to be very accurate with your focus. If it is even slightly off, or focused on the wrong part of the frame, your subject will come out soft.
 
Some things/tips to consider regarding aperture: 

• Most lenses have a "sweet spot" when it comes to sharpness at around f/8 to f/11. So this is a good aperture to use when DOF doesn't matter, such as when shooting a flat subject(everything at the same distance, or focusing at infinity, or pattern shots). So if aperture doesn't matter, and you have enough light(or a tripod), use an aperture between f/8 and f/11 for maximum sharpness.

• When you absolutely want to maximize Depth of Field, then you have to shrink the aperture as much as possible. You lose a little image quality to diffraction. Here again, many times it is negligible, you can test for yourself and see if it is something you can even detect, and find acceptable. This is especially necessary when shooting macro photos, since up close the Depth of Field is very shallow.

• When shooting the night sky, the priority is collecting as much light as possible, so the widest aperture possible is how I shoot those pictures.

• When I shoot landscapes, I go for sharpness, so I stick to f/8 to f/11. As long as  you focus at least a third of the way into the frame(distance wise), that should get all of it in sharp focus(in other words, just don't focus on the foreground). But I am not saying that's the best or only way to do that, just telling you how I do this.

Aperture is a key element of photography. Luckily, it is also not that difficult to understand. Just get out there and practice. One way to learn aperture is to set your camera to Aperture Priority ('Av' on a canon, 'A' on Nikon and most other cameras) mode. In this mode, you can just set the aperture you want, and the camera will pick the rest

ISO matters!

As I mentioned in the glossary post, ISO refers to the level of sensitivity to light of the image sensor or the film. The higher the ISO, the more sensitive it is. It basically comes down to this: The higher the ISO, the more noise you will see in your images. It becomes a tradeoff you need to make depending on the available light. ISO starts at 100 for most cameras, and goes up from there. At ISO 200, your sensor grabs twice as much light in the same amount of time as it would at ISO 100. And at ISO 400, it would grab twice as much light as at ISO 200, and four times as much as at ISO 100.

So in that sense, the math is pretty easy(assuming a constant aperture, for simplicity). If you were taking a picture that needed 1 second to expose properly at ISO 800, the exposure times would look like this:

  ISO     Shutter Speed/exposure time(in seconds)
  100     8
  200     4
  400     2
  800     1
  1600    1/2
  3200    1/4
  6400    1/8
  *assumes constant aperture
 
Ideally, you would always use be able to use ISO 100, or high ISOs would not give you any noise, but this is not the case. So the available light will dictate what ISO you should use. If there are moving subjects, like people, the shutter speed will need to be at least 1/50, and probably more like 1/100 to get crisp shots, so you dial that in, choose a wide aperture(since available light is the limiting factor), and then just see what ISO lets you expose the image properly. You will need to see what high ISOs look like in your camera, and determine if that is something you are okay with or not. 

Here is a real quick test I took, where the ISO increased in each shot, in order to demonstrate how ISO affects an image. The shutter speed had to be faster each time, to compensate for the ISO going up and collecting more light. 

As you can see, the noise level by 3200 are quite high, when compared to ISO 100. So this should illustrate why you don't want to shoot at high ISOs if you don't have to. But the available light dictates that. If you are taking night pictures, and you will be using a tripod, you may be able to drop the ISO to a low level(and minimize noise) and just increase the exposure time(use a slower shutter speed).

One thing that you will want to avoid, is using a high ISO when you didn't need to, because this needlessly degrades your image quality. If you are outside, shooting portraits or landscapes, and you're getting shutter speeds of 1/1000 but are using ISO 800, that is technically "wrong". Because for landscapes and portraits, you do not need such a fast shutter speed, so you can slow that down quite a bit, and then use that extra light to reduce your ISO. This happened to me numerous times when I was shooting in low light the night before, and the next day I would run out and then be taking pictures of whatever it may have been, but forgot to check the ISO was at. Just something to watch out for. 

Here are some shots at "high" ISOs. Just to show you that you shouldn't be afraid to crank it up when you need to. 

ISO 2000, 50mm, 1/100, f/1.8

ISO 3200, f/3.5, 8mm, 1/60

ISO 12800!(by accident!), f/3.5, 8mm, 45 seconds

In the end, like everything else, ISO is just something you will need to experiment and see what works for the type of photos you are taking. The levels of noise even at high ISOs like 1600, 3200, etc. using modern cameras are becoming more and more controlled and yielding very acceptable images. So don't be afraid to crank up the ISO when necessary. A sharp picture with a little noise that is better than a noiseless blurry picture, or no picture at all.

Learning to use shutter speed!

One of my earliest memories regarding photography that I can remember is a picture that was on the cover of the El Paso phonebook. I must have been 10 years old or so. It was interesting to me mostly because I had no idea how a picture like that could have been taken. It looked more like a painting to me. It was just a picture of the city shortly after sunset, and from a highpoint, so a rooftop somewhere overlooking I-10 and the Franklin mountain. I know now that it was a long exposure because I remember the light trails from the car lights along the highway, which is what made the most impact for me. Although apparently, it didn't occur to me to look it up! In my defense, I was a kid, and at the time, not everyone had a PC at home, or an internet connection. I sure didn't. So looking it up on google was not an option for me. I also didn't know any photographers I could ask.

Strangely enough, this image made enough of an impact on me that the first day I got the dSLR(after reading plenty of forums and photo blogs in preparation!) I tried to take a picture with light trails from the cars. So I grabbed the tripod, the camera, and went out the first night we had the camera. I was determined to get some trails in my pics and I knew it had something to do with the shutter speed. So I set the camera to 'Tv', which stands for Time Value, meaning shutter speed priority mode(on a Canon, 'S' would be the equivalent on a Nikon). Shutter Speed priority is a form of AUTO, in which you pick the shutter speed(and ISO if it isn't set to AUTO, but we'll get to that), and the camera picks the rest(really only the aperture is left). I setup at the nearest roundabout(I was living in England at the time), and tried it there. I tried 10"(seconds), then 20", then 30". It was EXACTLY what I had been looking for. By picking one simple setting, in this case the shutter speed, I was able to obtain a picture that had been in the back of my mind for many many years! It was very rewarding for me.

Here is one of the test shots that night:

f/13, 30 seconds, ISO 200, 20mm. One of the firsts pictures I ever took on a dSLR. I know the picture isn't much, but I was thrilled at being able to get light trails!

So it turns out that shutter speed is critical in creating the car light trails effect, but that is not all there is to shutter speed of course. You don't always want trails, and you don't always want a long exposure. I would say that once you can no longer hand hold an exposure, it would be fair to call it a "long" exposure. The easiest way to experiment with shutter speed is to set the camera to 'Tv'(on a canon, 'S' on a nikon) and see what different shutter speeds do. Here are some quick guidelines for what certain shutter speeds are good for:

*A guideline for the slowest shutter speed you can hand hold is:

     Limit for hand holding a shot = 1 / focal length you are shooting at
 
It is just a guideline, but it gives you an idea of what you can expect to be able to hand hold and still get a sharp picture. Some lenses have  IS(Image Stabilization,) VR(Vibration Reduction) on nikon lenses, which counter acts the shake, and allows you to shoot at slower shutter speeds and be able to hand hold the camera. Very useful nice to have.

**There is a guideline for how long that actually is:

      Max exposure before trails = 600 / focal length
 
Again, just a guideline, but it gives you a good starting point or limit if you want to avoid star trails when photographing the night sky. 

So there is a really basic summary of uses for certain shutter speeds. Here are a few examples, with images I have taken:

f/18 @18mm, 30 seconds total exposure(Stacked from 3, 10 second images)

f/2.5, 1/5000, ISO100, 50mm

f/2.0, 50mm, 1/80sec, ISO 400

f/3.5, 45 seconds, ISO 1600, 8mm fisheye

f/3.5, ISO 3200, 8mm fisheye, 3 hours total exposure(stacked from ~200 individual images)

f/11, ISO 100,  25mm, 2 seconds(I should have probably used a faster shutter speed)

This is all just a guide to give you a rough idea of where to start. I can write about it all I want, but it really comes down to you getting out there, setting it to Shutter Speed Priority ('Tv' on a canon, 'S' on a Nikon) or manual, and seeing how it affects your pictures.

Glossary

First, I will define some photography terms that will probably be used often in this blog. Don't worry about memorizing them now, we will mention them so much that it should become second nature to you at some point.

Disclaimer: I am trying to keep things simple, so if you want a more technical definition, this is not the place. I don't think that at this point it really adds to the discussion to get very technical.

Aperture - Basically, the size of the opening in the lens. This can be controlled(up to the lens' maximum and minimum apertures). It is written down as a fraction, such as f/1.4, f/5.6, f/8, f/11, etc. Since it is a division, the larger the f-number, the smaller the aperture(opening) and the less light it lets in(and the more DOF). So try to remember the smaller the f-number, the bigger the aperture. It is an inverse relationship.

Depth of Field(DOF) - In the photograph, the distance range that is in focus. Aperture and focal length have dramatic effects on DOF.

Exposure - A term for the amount of light that you allow to hit the film or sensor of the camera.

ISO - The level of sensitivity to light of the image sensor or the film. The higher the ISO, the more sensitive it is. Fun Fact: The initials come from the International Organization for Standardization, but they aren't really initials, and come from the Greek word for equal.

Focal Length - This has a somewhat complicated technical definition. For our purposes, suffice it to say that it is the number on your lens that is measured in millimeters(mm). Not the filter size, but the main specification of your lens. 18-55mm, or 50mm, or 70-300mm. That would the focal length. The smaller/shorter it is, the wider the angle of view. The longer the focal length, the more "zoomed in" it is. Most dSLRs come with what is known as a "crop sensor", or APS-C size sensor, meaning it is slightly smaller than the 35mm full frame sensors of the higher end "pro" cameras. This means that in some lenses, such as the very common(and awesome) nifty 50, the Canon EF 50mm f/1.8 II are actually about 1.6 times the focal length they say on there. So this lens would be 80mm on these cameras.

Live view - A feature on many dSLRs that allows you to see the image BEFORE you take it on the LCD display. Very useful for certain types of photos. If you had a point and shoot previously, or even saw one, you should be familiar with this as this is the ONLY way you can see what you are taking in most point and shoots, since they don't have an optical viewfinder(some have a digital one, which is kind of strange).

Shutter Speed(exposure time) - The amount of time that you let light hit the sensor or film. Measured in seconds. Usually denoted as a fraction when it is less than 1 second(1/500, 1/50, 1/6, etc.) and with a quotation mark when more than 1 second(1", 10", 30", etc.).

Viewfinder - Where you put your eye to see what the picture will look like. On dSLRs, it is optical, and what you see is what you get(for the most part).

White Balance(Color Temperature) -  Refers to the the adjustment of color mapping in order to render color tones correctly under artificial or different lighting(such as incandescent or fluorescent lighting). It can be done by choosing a preset(such as daylight, cloudy, color temperature, fluorescent, etc.) in camera or in post processing software(such as DPP, Aperture, Lightroom, Photoshop, etc.).

As I remember more terms, I will add them to this entry so you can reference it as needed as well as define them as they come up. Again, don't worry if this seems daunting or overwhelming, it will all fall into place.

So you got your first dSLR...what now?

This is probably not like any camera you have had before. There are way more controls, the camera is larger, it may seem daunting at first. The way most point and shoot cameras work is rather simple, from the user perspective. You just point, and shoot, hence the name. While this is very user friendly, you lose a lot of creative control. The camera decides everything for you, except what you're pointing it at. It calculates exposure time, aperture, ISO, decides what's "best" and then takes the picture for you. This may work for most people. But it leaves many of us craving more, unsatisfied, and with the feeling that you aren't capturing the moment the way you pictured(pun intended!) it in your head.

Enter the dSLR cameras. They are the "go to" camera for professionals and amateurs looking for more control and higher image quality. dSLR stands for Digital Single Lens Reflex. As the name suggests, they don't have to be digital, and in fact film SLRs existed long before the digital age. Now, it is far more common to see digital SLRs, but that doesn't mean that the concepts we will cover are any different on a film camera. The main difference is the medium in which the images are stored(film vs a memory card).

The first dSLR we got, in April 2011. A Canon EOS KissX4 / 550D / Rebel t2i. Sadly, it took a tumble into a creek, and we replaced it with a Canon EOS 7D.

It is important to note that having a dSLR does not automatically make your pictures better, or help you take better photos. You can get a $5000 camera, and leave it on AUTO. But your results will not be very different from what you were getting before. Not $5000 worth anyway. And probably not worth carrying that big thing around either. 

You will be surprised at how big a difference learning a few key concepts will make in your photography, and allow you to take more control over how your images will look.

f/11, 300mm, 1/400, ISO 400

This is not meant to put you off a dSLR, or discourage you in any way. It really isn't that hard, and it is the goal of this blog to get you past some of these hurdles and on your way to better photography. But that is not to say that it will happen without a conscious effort on your part to grasp these concepts and then go out and practice them! And I hate to be a buzz kill, but you will want to read that manual. And probably more than once. Yes, it is long. Yes, it is dry. But you will find out so many things about your camera and its controls that it will totally be worth it. At the very least, make sure you know where it is!

Why?

There are many reasons for wanting to get into photography. Some just like the art they see in photographs, and want to create some of their own. Some want memories. Others may like collecting pictures. You may just want to be able to document things. There are many many reasons, and you certainly don't need to have a dSLR to do these things. But depending on what you're trying to do, it will probably help. A lot.

f/8, 1/100, ISO 800, 47mm

This blog will attempt to take some of the mystery out of taking better photos. A good photo to you, may not be a good photo to me, so I don't mean in the artistic sense, but in the technical aspect of it. You can be picturing a certain image in your head, or you are trying to capture a moment, but if you don't understand how certain aspects of photography work, chances are that you will miss the opportunity or the resulting pictures will not be what you wanted them to be. And you can try and try again, but if you don't grasp what the different modes on your camera do, or what ISO, aperture, or shutter speed mean and how these affect a photo, you will have a much harder time being able to capture the things you want, or you will simply leave the camera in AUTO and let the camera do all of this for you. The problem with leaving it in AUTO is that many times the camera doesn't "get it right". After all, it is a program designed to calculate the best exposure, and no matter how much you spend on your camera equipment, it can't read your mind. So there will be times when you need to tell the camera what to do.

f/3.5, 8mm fisheye, ISO 1600, 56 minute exposure(Stacked from 75 images of 45 seconds each)

This blog will attempt to take some of the guesswork out of learning to use your camera in a way that is simple to understand. I am mainly writing it for my brother who just got a dSLR, and my sister, who will be getting one soon. I hope you find it helpful as well.

f/1.8, 50mm, ISO 1000, 1/250