#F stop and iso iso#

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.

#F stop and iso iso#

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.