![]() ![]() ![]() In January, I took a trip to my favorite place on the planet to take pictures–Yellowstone National Park. “Why do I need three tools to control the exposure? Wouldn't one suffice?” The answer is no, and I'll explain why with an example. Photo by Jim Harmer (Founder of Improve Photography) Right now, you will commonly find new DSLRs that advertise expandable ISO ranges.īighorn sheep in Yellowstone National Park. Since each camera is different, you would do well to do a few tests with your camera to see how high of an ISO you can shoot at without making the image overly grainy. A few years ago, only the highest-end pro DSLR cameras could achieve 2,000 ISO, and now even entry-level DSLR cameras can shoot at this level. Camera companies are constantly improving the ability of cameras to use high ISOs without as much grain. What constitutes a “high” ISO is constantly changing. Have you ever taken a picture at night with your cell phone or your pocket camera, and noticed that it looks really grainy? That is because the camera tried to compensate for the dark scene by choosing a high ISO, which causes more grain. ![]() Digital noise is apparent when a photo looks grainy. The drawback to increasing the ISO is that it makes the picture noisier. Every once in a while, you'll hear an older photographer pronounce it “I-so”, but almost everyone pronounces it “I.S.O.” The ISO controls the exposure by using software in the camera to make it extra sensitive to light.Ī high ISO such as ISO 1,600 will produce a brighter picture than a lower ISO such as ISO 100. It is always just called ISO even though it really stands for International Organization for Standardization. The funny thing about ISO is that it is an acronym, but nobody really knows what it stands for. The next question that most people ask is, how slow of a shutter speed can you use and still get a sharp picture? My blog post on Minimum Shutter Speeds will answer your question! At this speed, my hand is still moving, but the camera takes the picture so fast that my hand travels only such a small distance that it is not noticeable in the picture. To get rid of the blur, you need to increase the shutter speed to around 1/320th of a second. If you take a picture of me with a shutter speed of 1/30th of a second, then my hand will have moved in the time that the camera is recording the picture. Imagine me sitting here at my computer desk waving to you (you don't have to imagine very hard if you just look at the picture on the right). If you think about it, it makes sense that the shutter speed controls how much blur is in the picture. The shutter speed is also principally responsible for controlling the amount of blur in a picture. Just as the aperture affects the exposure as well as the depth-of field, the shutter affects more than just the exposure. That's me! Typing away on this article from my studio in Meridian, Idaho. Take a minute and make sure you understand this info before moving on. If you, like me, are more of a visual learner, then I think this graphic will help solidify the information about aperture. ![]() If you want to take a picture of a sweeping mountain vista, you'd want to use a small aperture size (high f-stop number) so that the entire scene is in sharp focus. If you want to take a picture of a person with a blurry background, you'd use shallow depth of field. Depth-of-field is how much of the picture is sharp, and how much is blurry. The aperture also controls the depth-of-field. The size of the aperture controls more than the brightness or darkness of the picture, though. If you take a picture and it's too dark at f/5.6, would you choose a lower f-stop number or a higher one? Yep! You'd choose a lower f-stop number, which opens up the aperture to let in more light. Let's test your knowledge to make sure you have it down. A high f-stop like f-22 means that the aperture hole is quite small, and a low f-stop like f/3.5 means that the aperture is wide open. Simple! Aperture sizes are measured by f-stops. How do you fix it? Simply choose a smaller aperture. So suppose you take a picture that is too bright. Obviously, if you shoot with the aperture wide open, then more light is allowed into the camera than if the aperture is closed down to only allow a tiny hole of light to enter the camera. The blades create a octagonal shape that can be widened (we photogs call it shooting “wide open”), or closed down to a small hole. The aperture is a small set of blades in the lens that controls how much light will enter the camera. ![]()
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