The ISO is also known as the film speed; it is a measurement of the film’s sensitivity to light. Of course “film speed” is a term left over from days when all cameras used film instead of computer chips. In those days, they had to use a physical substance called silver halide (or silver salt) coated onto film in order to get a photo. (A little background information: Silver salt changes its chemical composition in the presence of light. Just as the name implies, the silver salt is made up of granules, just like table salt.) They found out that the larger the grain of silver salt, the more reactive or sensitive to light it was; ergo, larger grains meant less light was needed to take a photograph. This was great news for taking photographs in low light; it had one big drawback, however. If the grains were larger, they were more visible in the photo. This caused it to look, dare I say, grainy.
Just like film, your digital camera has settings to alter the sensitivity of light in the sensory chip. The higher the ISO, less light needed to take a picture. Just like film, the sensor has its own grain, but in the form of noise. What does all of this mean? Consider the bullet points below.
- Higher ISO = Less light is needed to take a photo, but there is more noise in the photo.
- Lower ISO = More light is needed to take a photo, but sharper images are produced.
- As a general rule, you want to use the lowest ISO possible in any given situation.
If sufficient light is not available, can you use the flash with a low ISO? Using the flash is one option to help maintain sharper images with lower ISO numbers, that is if your subject is only a few feet away and you don’t care about including the background.
Let’s say, per chance, you are visiting family for the holidays and you miraculously get everyone to grudgingly squeeze together, close enough to fit into the viewfinder of your camera, in order to prove that everyone dealt with one another under a single roof for at least one day that year. Your goal is to get a sharp photo of the group. This would be an ideal situation to use a flash paired with an ISO set to 100.
If, on the other hand, you are visiting a museum that does not allow flash photography, you will need to increase your ISO so you can shoot at shutter speeds high enough to get clear photos. The noise is unavoidable but in some situations it can be better than no photo at all.
As another example, let’s say you are at the beach in the evening; you would like to take a photo of you significant other. You could use the flash with a low ISO but the background would turn out black. If you were to forgo the flash and increase the ISO, you introduce noise but you get the whole scene.
It is now time. I want you to set your camera to manual mode. It is usually the M setting. Just as it sounds, this puts the camera in your hands. Each setting is controlled by you, manually. This means that you will have to set three things in order to shoot: the f/stop, the shutter speed, and the ISO. I know it sounds like a lot to set before taking a photo, so I’ll break it down.
Get your manual and find out how to change your ISO. Go ahead, I’ll wait…………….
Your First Manual Shot
Now that you know how to change the ISO, I am going to assume you are sitting inside, which is good. Perhaps the light isn’t all that bright where inside, but that’s OK. Pick up your camera and follow along.
- Set your camera to manual mode.
- Set the ISO to the lowest setting, usually 100.
- Point the camera at anything in front of you. It doesn’t have to be anything interesting.
- Set your f/stop to whatever you want for that object.
- Now press the shutter button half way. This will allow the camera to auto focus on the subject and the camera’s built in light meter will determine if the photo is properly exposed. You will notice a meter that looks like this in the viewfinder or on the screen.
- You can let go of the shutter button and adjust the shutter speed until the little arrow is in the center, indicating proper exposure. If the shutter speed is slower than 1/60, it would be difficult to maintain the shot if physically holding the camera.
- If that is the case, adjust the ISO to about 400. Aim the camera and push the shutter button half way again.
- Adjust the shutter speed so the arrow is in the middle, again, indicating proper exposure.
- Once the arrow is in the middle, you are set to take the photo. Press the shutter button down all the way to take the photo.
- Look at the result.
- You did it! You have now used all three pillars of photography!
All of this sounds so complicated. Can we simplify the steps? Yes! Each one of these settings doesn’t have to be set before each shot. The ISO can be set once per environment, usually. If you are in a museum or outside on a sunny day, your lighting environment isn’t going to change much from photo to photo. Once you find a good ISO for that environment, you don’t really have to adjust it for every shot. That leaves you with just the f/stop and shutter speed to worry about.
There will always be situations where you only want to worry about the f/stop or the shutter speed, hence the purpose of aperture priority mode and shutter priority mode. Being able to use manual mode simply allows you to take full control of your camera, as you see fit.
Go out and shoot! Set your camera to manual and take photos of things. Fill up that memory card, erase it and fill it up again. Play with the settings. Instead of adjusting so that the shot is set to proper exposure, take a photo with the arrow to the left or the right of the middle. Notice how that leaves your image slightly under or over exposed. Use that to your advantage. Some photos look better a little under exposed. The purpose of this assignment is to get used to manipulating all three settings until it’s second nature. As always, feel free to contact me if you are having problems.
I hope you are enjoying the lessons and I really hope they are helpful. The next lesson will be about how to frame a shot using the rule of thirds.
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