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fov和焦距的关系

It is specific for zoom lenses rather than fix focus lens. Zoom ratio is the ratio of the focal length at the telephoto end to that at the wide end. A zoom lens can change the size of an object appearing on the monitor to the extent specified by the zoom ratio.

fov参数

Provide the image sensor aspect ratio is 4:3, we can calculate the horizontal FOV = 75 degree, and diagonal FOV = 94 degree. From the Figure 1 we can also calculate the focal length by the equation : f/d = h/H equals to f = d x (h/H). Now we can get f = 15 x (2.4/16) = 2.25mm.

Minimum object distance (M.O.D.) indicates how close the lens can be placed to the object for shooting. It is measured from the vertex of the front glass of the lens. Sometimes, you can still focus the lens to very close object by manually focusing the lens. But you have to trade off between the close object and far away object, because only one can be well focused, the other end will be blurry. So the MOD parameter is specified for focusing on both close and far away object.

A lens produces images in the form of a circle, called the image circle, also know as optical format. In a CCTV camera, the imaging element has a rectangular sensor area (the image size) that detects the image produced within the image circle. The ratio of the length of the horizontal to vertical sides of a video image is called the aspect ratio, which is normally 4:3 (H:V) for a standard CCTV camera.

The lens optical format should match with target image sensor like the left most photo in the Figure3. If lens optical format and image size doesn’t match, it also works. But when the lens optical format is larger than image sensor, the lens FOV will be reduced; and when the lens optical format is smaller than image size there will be dark areas around the corners and some portion of the sensor area is not useful.

FOV tofocal length calculator

FOV tofocal length

The FOV is also called angle of view which is the shooting range that can be viewed by the lens given a specified image size. It is usually expressed in degrees. Normally the angle of view is measured assuming a lens is focused at infinity. The angle of view can be calculated if the focal length and image size are known.

field of view中文

Parallel incident light transmitted into a convex lens converges to a point on the optical axis. This point is the focal point of the lens. The distance between the principle point in the optical system and the focal point is referred to as the focal length. For a single thin lens, the focal length is equal to the distance between the center of the lens and the focal point.

After you've chosen your lens type, there are added features you may want to include as you order your perfect pair of eyeglasses or sunglasses. These features could be different types of coatings available, each which offers a special type of protection for your new lenses and for your eyes.

Anti-Reflective Coating Anti-reflective coating or AR coating can make a huge difference in how comfortable you are looking through your new lenses. The special formulation of an AR coating is applied to both sides of the lens in order to dramatically lessen the quantity of glare that bounces off your lenses and into your eyes. A good AR coating helps block glare from sunlight, overhead lights, light from the computer display screen or even car headlights at night. If you hate the sensation of seeing your own eye look back at you because of glare in your glasses, an anti-reflective coating will eliminate that. An anti-reflective coating can make your glasses have a better appearance to other people as well. Because the glare is diminished, others who are looking at you are able to see your eyes directly without having the surrounding lights casting unflattering glares on the eyeglass lenses. An AR coating can be applied to sunglasses as well to help with the impact of sunlight as it passes through the glasses. This may enable you to see better with your sunglasses on a sunny day even if you have a lighter tinted lens. For those who choose AR coating, you'll want to ask about care of your lenses. Eyeglasses with AR coating will need to be cleaned with unique cleansers and should under no circumstances be cleaned with a dry fabric without wetting the lens first. This can result in scratches that will be very noticeable with an AR coated eyeglass lens.

fov是什么

Distance between vertex of the rear element lens and image sensor. Sometimes the lens comes with very short focal length, so you should use proper lens holder to match the back focal length of the lenses. For example the fisheye lens LS-40180 can’t use any other lens holders except the mating lens holder designed specific for this lens.

FOVcalculator

Given there is a QR code scanner application, we have a 1/4″ image sensor, and the camera is 15mm away from the QR code, the QR code size is 16mm x 16mm. How we will study how to calculate the lens FOV and select a proper lens for QR code scanner application.

The lens is used to converge the light beams to an image plane on the image sensor for an clear and sharp frame, which is also an important part of the optical systems. Arducam has cultivated deeply into the optical systems and vision solution for decades. We have plenty of excellent Lens featured with many attributes for various kinds of the camera module.

If we want to use full image plane to capture the QR code, from the Figure 1 we can calculate the vertical FOV as 2 x arctan(H/2d). Where H is the height of the QR code and equals to 16mm. So the vertical FOV θ = 2 x arctan(16/2/15) = 56 degree.

Note that all the calculation is based on pinhole camera model, the real lens focus calculation is more complex the focal length will be different. The formula here just gives you a basic idea about the lens. You can choose the proper lens according to the FOV listed on the below table. And sometimes we might not need the QR code cover the entire image plane for the margin of scanning area, in this case we can choose larger FOV lens than we calculated above.

Scratch-Resistant Coating Sadly, no eyeglass lens can be 100% scratch proof. A scratch-resistant coating is the next best thing! When you order this coating on your lenses, your optician will treat both the front and the back of the lenses with a special solution that will make them more durable and scratch-resistant. If you are the type of person who forgets your glasses case or you tend to clean your glasses with the bottom of your shirt, this type of coating will offer you some protection from shallow scratches. This lens coating is also great for children's eyeglasses.

Lens Tints Looking for a little color in your lenses? Maybe you want some computer glasses to reduce some of the blue light? Ask your optician about the full range of lens tint options that would enhance your eyeglass lenses for your current lifestyle!