Aperture

In the simplest of terms, aperture is a hole that allows light through. This also happens to be the third part of the exposure triangle, and can be one of the hardest concepts to grasp. Aperture is measured in “f-stops” and the higher the number, the smaller the opening. For example f/4 is a larger opening than f/22. Moving from one f-stop to the next doubles or halves the amount of light that gets in.

Aperture also controls the “depth of field” (DOF) or the parts of the image that are in focus. Having a large depth of field means most of the image, foreground to background, will be in focus. This means a relatively small aperture was used, like f/16 for example. A small, or shallow depth of field means only a small part of the image is in focus and the rest will be fuzzy. To get this kind of look, you want a big or wide aperture; something around f/2.8.

This can be a difficult concept to grasp. It’s somewhat opposite of what you think. But something that helped me when I was first learning it is small numbers means small DOF and large numbers means large DOF.

The first image was shot at f/22 and the second at f/2.8.

The first image was shot at f/22 and the second at f/2.8.

Like with shutter speed, different styles of photography favor deep or shallow DOF. More often than not you’ll find landscape photographers using small apertures in ensure the whole scene is in focus, from the foreground all the way back to the horizon. Portrait and macro photographers will use wide apertures to isolate the subject by allowing the background to fall out of focus.

I hope you have found this helpful. Next week we’ll combine the three parts of the exposure triangle and talk about how they’re related to each other.

Shutter Speed

Last week I talked about ISO. But that’s only a third of what makes up exposure. This week I want to talk about another part of the triangle. Shutter speed, or exposure time, is how fast the shutter moves or how long the shutter of the camera is open, exposing either the piece of film or digital sensor to light and controls how much movement is in the image. This is measured in seconds for long exposures and fractions of seconds for faster exposures. Unless you plan to use a tripod or some other form of image stabilization, you are going to want to stick to a speed of 1/60th of a second, or faster. Anything slower than this, you are likely to introduce what’s called “camera shake” when hand-holding the camera. This is when the camera moves during the exposure and the whole image is blurred because of this.

When you’re choosing what shutter speed to use, take a look at the scene and see if there’s any movement. If there is, you need to decide how you want to capture it. Do you want to freeze the action, or allow it to blur? Sports and nature photographers almost always want to freeze the action. To do this they’ll often use a shutter speed in the thousandths of a second. Take this hummingbird for example. It was shot at 1/2000th of a second, which froze all of the motion of its fast-beating wings.

Motion isn’t always a bad thing. Many landscape photographers will carry a variety of neutral density filterers with them so they can slow down their shutter speed if they’re stuck shooting during the day. Notice the smoothness of the water as it goes over the falls in this shot of the Des Moines skyline. Even with a high ISO setting, the exposure took roughly half a second to create. This doesn't sound like a slow shutterspeed, especially when it only takes about a third of a second to bink your eyes, but remember hand-holding your camera at anything slower than 1/60th of a second can introduce blur you weren't looking for.

ISO/ASA

When shooting in manual mode, meaning having full control over an image’s exposure, there are three things that are directly related to each other: Shutter Speed, Aperture, and ISO.

ISO is the camera’s level of sensitivity to light. In the days before digital ISO (or ASA) referred to the “speed”, or how quickly light is absorbed. The higher the number the faster the absorption rate. As the number doubles so does the speed of light absorption: ISO 200 is twice as fast as 100, 400 is four times as fast, 800 is 8 times as fast, and so on. Now swap the piece of film for an image sensor, and the numbers carry over in the same way.

When to use a “slow” speed vs. a “fast” speed:

If you’re in a situation where there is a lot of light, you’re going to want a low ISO. A couple examples might be while you’re playing at the beach, or skiing down a snow covered hill in the middle of a cloudless day. In these situations you are going to have a ton of light both coming from the sun, and reflected off the ground. Be careful though, this kind of light can trick the camera into thinking there’s more light than there actually is.

In order to use your camera in low light situations, like indoors, without the use of a tripod or flash, you may need to boost the ISO. Be careful though, high ISO comes at a cost. The higher you go, the more noise and grain gets introduced into the image, and degrades the quality. Because of this, I will sometimes limit my ISO to something like 800 for the highest quality.

Here is an example of what camera noise can look like at a high ISO setting.

In the days of film, as soon as you put a roll of ISO 100 into your camera, you were stuck at that speed for the entire roll. The digital image sensors of today allow you the ability to change as you see fit. You could be shooting at ISO 100 outside for one frame, and a minute later be shooting at ISO 3200 in room lit by a single candle.

There is a bit of confusion as to where the term ISO comes from, and its pronunciation. A lot of people say, because you’ll always find it in all caps, it’s an acronym for “International Standards Organization”, and pronounce it “eye-es-oh”. This is actually wrong. There’s no such thing as the “International Standards Organization.” There is however the International Organization for Standardization, which sets numbers for all kinds of industries like engineering and manufacturing globally. So why isn’t it IOS? Instead of choosing an acronym to represent the company, they decided to use a word. ISO comes from the Greek word ISOS, which means “equal”. Therefore the correct pronunciation is “eye-so”.

The Camera

Every camera is the same, whether it is the latest and greatest digital medium format, boasting an 80 megapixel sensor, to the Kodak Brownie cameras of yesterday. They all boil down to being a light-tight box with a hole in one side and some kind of shutter for the photographer to control the exposure. This could range from a piece of tape covering the hole of a pinhole camera, to the most sophisticated system ever engineered with
internal springs, gears, and computers.

Cameras have been around long before even the invention of the photograph. The Camera Obscura, when translated from Latin means Dark Room, was used by early artists to more accurately record the world around them. Children today will often make smaller versions in science classes to be able to safely watch a solar eclipse. Like the pinhole, these too can range in size, material, and complexity. Some of the more fun ones to experience are made from blacking out the windows, except for a small single hole, and turning an entire room into a camera. However, without the use of lenses or prisms, the image projected on the opposite wall may be slightly out of focus,and will be inverted both horizontally and vertically.

But what is the best camera? Commercial photographer Chase Jarvis once said, “The best camera is the one that’s with you.” Almost everyone these days carry a camera with them everywhere they go. If you go to any tourist attraction, you will see the majority of the photographs at the site being taken by some kind of mobile device. Most of these images are just snapshots, will never see the light of day, and will quickly be forgotten. However, in the hands of someone who takes the time to properly compose and edit theirimage, the cell phone can be a powerful tool to create with stunning results.

Regardless of how sophistocated your camera may be, you need to spend time with it in order to be able to use it effectivly. I will always take whatever camera is new to my collection, and solely shoot with it until I know its ins-and-outs. Don't be afraid to sit down and push every button, turn all of the dials, dig through each layer of the settings menu, and experiment. The more comfortable you are with the tool, the better the end product will be.

Why?

The idea of doing a blog is not a novel concept for me, especially when it comes to the topic of photography. Several years ago I had a "daily photo blog" going, and was doing great with keeping it going for about six months. Then it all came to an abrupt stop when my camera bag was stolen out of my car, and with it all of my photography gear. All except the camera in my phone, but that had a cracked lense. It was very difficult to keep posting images on a daily basis without having working equipment.

So why start up another blog now? The answer is multi-faceted, with the first simply being part of a class assignment. Don’t worry though, the rest are far more poignant.

Doing a blog such as this is a great opportunity for personal growth. There is no one in the world who is incapable of improving their writing skills. I see blogging as an excellent way to practice these skills. We’ve all, especially in a school setting, been asked to describe something in our own words. Sometimes this came easier than others, and for me was usually dependent on whether I did the assigned reading or not. However, being able to do so effectively meant I understood the material being taught. If I can make some of the intangible concepts of photography tangible by putting them into words, I will undoubtedly have a stronger grasp, and will ultimately become a better photographer. It’s said the best way to understand a subject, is to teach it to another person. If my words are able to make it easier for someone else to understand, all the better.

I’ve had a goal of becoming an educator for a long time. Some of my absolute favorite memories of being in the Boy Scouts are of when I was working with the new scouts that had just crossed over, teaching them the basic knots. I started off my college experience as a music ed. major. When that wasn’t working out I wanted to go into Deaf studies and while taking some upper-level American Sign Language (ASL) courses, I loved signing with the new ASL students and helping them improve. Even when I was volunteering with Guide Dogs for the Blind there was a strong sense of pride when I was able to get whichever puppy in training I had at the time to follow the basic obedience commands, or walk up an open staircase with no trouble after they had been too afraid to do so initially.

Providing those moments of inspiration is why I’m a photographer, why I want to be an educator, and why I’m writing this blog.