![]() It is impossible to make an independent change in one of the elements and not obtain an opposite effect in how the other elements affect the image, and ultimately change the EV. Increasing the ISO, allows for shooting in lower light situations, but you increase the amount of digital noise inherent in the photo. However, reducing shutter speed (keeping the shutter open longer) also increases the amount of light hitting the image sensor, so everything is brighter. Reducing the shutter speed affects how motion is captured, in that this can cause the background or subject to become blurry. A tripod mount for the camera will also eliminate camera shake, but it can slow down your response time for framing and focusing the critter.When these three elements are combined, they represent a given exposure value (EV) for a given setting.Īny change in any one of the three elements will have a measurable and specific impact on how the remaining two elements react to expose the film frame or image sensor and how the image ultimately looks.įor example, if you increase the f-stop, you decrease the size of the lens’ diaphragm thus reducing the amount of light hitting the image sensor, but also increasing the DOF (depth of field) in the final image. This, of course, may mandate a big aperture or high ISO speed to accommodate the proper exposure. A 200mm lens calls for 1/250 and that 600mm lens needs 1/600th. So, with a 28mm wide-angle lens, you’d want 1/30 second or faster. The general rule for steadying a handheld camera is to use a shutter speed equal to or faster than your lens’ focal length expressed as a fraction. You, however, will not be able to hold that long lens without shaking it. The rodent will freeze many times as it pops in and out of view. Then you’ll need to set a shutter speed sufficient to stop - yourself, not the squirrel. First, you’ll have to be darn good at focusing or use an effective auto-focus. Let’s say you’re using a 600mm lens and trying to freeze a ground squirrel that’s popping in and out of the grass. ![]() Super-telephoto shot of a ground squirrel. Just be certain the wind isn’t blurring your foreground flowers. ![]() This frees you to select both a small aperture (big f-stop number) for maximum depth and small ISO number for minimal noise. If you can steady the camera on a tripod or bean bag, shutter speed can go as low as necessary for proper exposure. Let’s say you have a field of wildflowers in the foreground with green hills rising beyond and mountains jutting into a blue sky - and you want all of it sharp. Because flowers are soft or suggest delicacy, avoiding ISO noise can be a significant esthetic choice, in which case you’ll have to wait for calm conditions to get your shots. You may need to crank up ISO on this one. To compensate, you’ll want to stop down to f-16, f-22 or f-32. ![]() Why? Because small flowers require a close approach and close focus, which limits depth of field. A blowing flower can blur at 1/250 sec., but you probably don’t want to gain shutter speed by opening the aperture on this shot. Experiment with ISO settings in your camera to understand its levels of noise.įlowers in the wind. This increases noise, but that’s better than a blurry subject. On gray days you may need ISO speeds above 3200. If you choose a wide open aperture, say f-4 on a 400mm telephoto, you’ll probably need to crank up your ISO setting to reach 1/1000 second shutter. This requires bright light, a wide-open aperture and usually a fairly high ISO setting. Some big, slow birds can be “frozen” at 1/250, but most need 1/500 or faster.
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