Idea: A new automatic setting for cameras
There’s a rule of thumb for long lenses and shutter speeds: to handhold a camera without noticeable motion blur, your shutter speed should be no slower than the inverse of your focal length. So for a 50mm lens, you can safely handhold at 1/50 of a second or faster. If you have a long telephoto, like say a 200mm lens, you shouldn’t try to handhold at slower than 1/200 of a second.
But what if you’re using a zoom lens, and your focal length varies from one shot to another as you capture wide shots and close-ups to tell the story of whatever you’re shooting? Wouldn’t it be great if your camera had a setting to automatically adjust your shutter speed (and appropriately your aperture to maintain exposure) when you zoom so your tight shots are still nice and sharp?
You already have an aperture priority mode that adjusts your shutter speed if you change the aperture, and a shutter priority mode that does the opposite. So why not add focal length to the automatic equation, too?
It will not be useful in all situations, of course. In dim light, your lens might not be able to open up enough to compensate for the loss of light when the shutter speed increases as you zoom. But in other situations, this setting could be just the thing that keeps you taking sharp photos instead of smeary messes.