Taking the scary out of Manual: Shutter Speed, Aperture, and ISO Camera Basics
Auto mode on your camera is so easy. You turn the camera on, press the shutter, and boom — you’ve got a picture. You have a picture based on the settings that your camera saw fit to achieve the proper exposure, aka brightness of the image. But what if you were taking a picture of a bird? Perhaps you need a fast shutter speed to freeze the flap of its wings, but your camera can’t read your mind and know that, it’s just focused on the proper exposure. Leaving you with a correctly exposed bird with blurry wings. Or maybe you want to take a picture of a woodland scene and you want every tree in focus. But the camera thought it was a little dark in the woods, opened up your aperture, and left you with one tree in focus and the rest out of focus from the shallow depth of field. But hey, it’s exposed properly. Having a picture exposed properly isn’t good enough to create a top notch image. You need to know how to use your camera, and allow yourself the creative freedom you need. So put your camera in manual and follow along for a quick summary of camera basics: shutter speed, aperture, and ISO.
1. Shutter Speed
The shutter speed on your camera is represented as a fraction of a second or in full seconds. The smaller fractions mean a faster shutter speed and the larger fractions/full seconds mean a slower shutter speed. For example, 1/250th of second is a faster shutter speed than 1/4th of a second. The speed of your shutter determines the length of time that light will be let into your camera’s sensor. A slower shutter speed will let more light into your sensor than a fast shutter. Also associated with the speed of your shutter is the amount of motion shown in the image. A slower shutter speed will show more motion, meaning there will be portions of the image that are blurred like a waterfall, leaves in the wind, and the wings of a bird. So, when considering shutter speed you need to think about two things: the light needed to properly expose the image, and the motion you are trying to capture. If you need to increase the exposure of your image, then slow down your shutter speed. If you need to have a fast shutter speed and increase the exposure of the image, then you must compensate with aperture or ISO. So read on and we’ll sort that out.
This is the number next to the f on your camera. The aperture above anything else, will control the depth of field of the image. By depth of field, I mean the amount of the image that is in focus. A large depth of field will keep more of the image in focus, while a shallow depth of field will keep a slim section in focus (like portrait mode on the iphone). A lower aperture, like f2.8 or f4, will have a very shallow depth of field with great bokeh to the image. A higher aperture, like f16 or f18, will have a large depth of field great for something like a landscape image. The aperture also, like shutter speed, determines how much light is let into your camera’s sensor. A lower aperture (f2.8) will let in more light than a higher aperture (f18). So here you’ll need to consider the depth of field needed in your image, and the light need to expose your image correctly. Perhaps your image required a certain shutter speed, but aperture is less important or vice versa. You can use the two in combination to achieve the correct exposure. But what if you need a fast shutter and a high aperture? Your image is probably greatly underexposed. Fortunately, there’s another piece to this puzzle, ISO.
ISO is really your camera’s sensitivity to light. The key to ISO is how it affects the quality of your image. A low ISO, like 100, will produce a high quality image with minimal grain. A high ISO, like 28000, will produce a low quality image with a large amount of graininess. This is crucial. To keep things simple I usually try to keep my ISO as low as possible. The other key part of ISO is how it affects the exposure of your image. A higher ISO means your camera’s sensor will be more sensitive to light, creating a brighter exposure. So, if your image requires a specific shutter speed and aperture, this is your third opportunity to compensate for your exposure.
Using Manual mode on your camera is a difficult thing. I could spend hours talking about each one of these three categories. But hopefully this quick summary was helpful and will make you become more comfortable in using your camera’s full creative abilities. As always, I really appreciate you taking the time to read and hope you found something in here helpful. Talk to you all next Tuesday!