I feel like I need to start by explaining a couple of photography terms. Shutter speed and Aperture are two important settings used by all cameras. You don’t have to set them with point and shoot cameras or when you set your 35mm camera on Fully Automatic. But an understanding of each term will help you expand your world of photography.
Shutter speed is how fast the camera takes a photo. The shutter opens to let in the light, then closes to stop the light. If you let in too little light, your photo is too dark. Conversely, if you let in too much light, it will be over-exposed and washed-out. If you want to catch a photo of something sitting still, you can take your time with the shutter speed. But if you want a photo of a sprinter, you better use a short shutter speed or the person will be blurred. A rule of thumb for a portrait is to use the inverse of the focal length for the lens you are using. So if you have a 50mm lens, you would set the shutter speed to 1/50 of a second. If you have image stabilization on your lens you have a little more wiggle room and could use a slower shutter speed. But I would not recommend it. The lens will have a little switch to turn IS (image stabilization) on or off. Don’t confuse this with the switch to turn automatic focus on or off. These settings assume you have a still subject cooperating with your photography efforts. You can find numerous suggestions of shutter speeds online for any photographic endeavor you want to pursue. Just remember, the slower the shutter speed, the more likely even slight movements of your hand holding the camera will cause blur in your photo.
Aperture is the function that works in conjunction with shutter speed to let light in or restrict light for photo composition. Aperture is the opening of the camera lens. A smaller hole lets in less light. A larger hole lets in more light. I’m a sci-fi fan. If you’ve ever watched the sci-fi hit “Stargate”, the aperture of the camera looks just like the opening and closing of the Stargate, minus the explosive bubble feature. The blades of the camera lens “diaphragm” is what makes your aperture more open or more closed. If you put in a setting of a wide open aperture, you will let in more light and will allow the camera to use a faster shutter speed. Keeping the camera at the same shutter speed with a narrow, nearly closed aperture, will make the photo have less light. Your photo would be too dark.
Aperture numbers are a bit confusing, so I want to explain it a little. Put simply, the smaller the aperture number on your camera, the more open the diaphragm. So a big aperture number means the lens is almost closed with a tiny pin-hole opening. A small aperture number means more light, and you can use a faster shutter speed. A big number means less light, and you must use a slower shutter speed. Each lens comes with information on how big or small the aperture can go. If you take a lot of dark or inside photos, you will want a lens that goes to wider apertures. Aperture is also referred to as the F-stop. The widest aperture of my personal lenses is F/1.8, so it can get better photos with less light. It also provides beautiful blur for the background of portrait photos.
Another note about apertures concerns physics. Don’t worry. I’ll hold your hand through this part. But it’s worth it to understand the physics of photography. Aperture helps control what is called Depth of Field. If you use the “portrait” setting on your cell phone to take a picture of someone, the background appears blurred. The photo is just focused on the person and anything behind them is blurred. This is called a shallow depth of field. The camera is focused very close to the lens. A wide open aperture results in focus close to the camera with everything further away appearing blurred. A pin-point opening of the aperture results in everything including far away objects in focus. Photographers refer to the blurred part of a portrait as bokeh. Different lenses with wide aperture settings can help create a nice bokeh to help artistically refine your photo. Cell phone apps and photo processing programs can create a bokeh appearance after the photo has been taken, but it is not as clean and beautiful as that from a quality lens.
I hope this has helped you make more sense of shutter speed and aperture. Next week I will write about ISO, the International Organization for Standardization, and why it’s important for photography. Keep finding the beauty in this world!
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