How many pixels is f 1.7?

F 1.7 should be the aperture, not the pixel size.

Aperture is a component used to control the aperture of the lens on the camera, so as to control the depth of field, the imaging quality of the lens and the amount of light entering with the shutter.

The aperture stop of the photographic lens can be adjusted to control the amount of light reaching the film or image sensor. Combined with the change of shutter speed, the aperture size will adjust the exposure of film or image sensor. Generally speaking, a fast shutter needs a larger aperture to ensure sufficient exposure, while a slow shutter needs a smaller aperture to avoid overexposure.

Reducing the aperture size (increasing the f value) provides less light for the sensor and increases the depth of field, which describes the degree to which objects closer or farther from the actual focal plane seem to be in focus. Generally speaking, the smaller the aperture (the larger the F value), the greater the distance between the subject and the focal plane, while still being clearly visible.

The lens aperture is usually designated as f, that is, the ratio of focal length to effective aperture diameter. The lens usually has a group marked with "f-stops", and the f number can be set to. A lower F value means that a larger aperture opening allows more light to reach the film or image sensor.

The photographic term "first aperture" refers to the change of F value √? 2 (about 1.4 1) times, which corresponds to 2 times of light intensity change.

Aperture priority is a semi-automatic shooting mode used in cameras. It allows the photographer to choose the aperture setting, let the camera decide the shutter speed and sometimes the ISO sensitivity to get the correct exposure. This is also called aperture priority automatic exposure, A mode, AV mode (aperture value mode) or semi-automatic mode.

Optimum aperture

Optically, when the lens is reduced, the defocus blur at the depth of field (DOF) limit will decrease, but the diffraction blur will increase.

The existence of these two opposing factors means combining the points with the smallest fuzzy points (Gibson 1975? , 64)。 At this time, the F value is the best for image clarity, and for a given depth of field-a wider aperture (lower F value) will lead to more defocus, while a narrower aperture (higher F value) will lead to more diffraction.

As far as performance is concerned, the lens usually does not achieve the best performance when it is fully open, so it usually has better definition in some cases-please note that this is the definition of the key focal plane, regardless of the depth of field.

Beyond a certain point, stopping has no further benefit to sharpness, and diffraction begins to become significant. So there is an optimum, usually in F? /4 –? f？ /8, depending on the lens, sharpness is the best, although some lenses are designed to perform best when they are fully open. How much difference does this have between shots and how much practical impact does this have? There are different opinions.