Popular about the lens device. video art

BOOKS AND ARTICLES
Free library / Directory / video art

Popular about lens design

video art

A lens is an optical device that projects an image onto a plane. In optics, it is considered as equivalent to a converging lens.

The parameters that determine the consumer properties of lenses have long been defined, and are well known to everyone who has been involved in photography. Therefore, the figures that can be found on the lenses of video cameras are not a mystery to them.

The rest need a little explanation.

Usually, two values can be found on the lens (or in the performance characteristics of the camera).

This is: f - always two digits, from some to some.

For example: f=3,6~36mm. and F is usually a single digit, eg F=1.8.

But sometimes there are two, for example F=1.8-3.0

Let's start with a small f, as it is simpler, and necessary to explain the second value.

Under this letter lies the focal length.

Focal length is the distance from the plane on which the image is focused (in our case it is CCD, in cameras and film cameras) to the thin lens of the objective.

To exclude the effect of focusing, the object that is projected onto the CCD must be at infinity.

In other words, the focal length is the distance between a thin lens and an image of an infinitely distant object.

Two numbers - indicate that the lens has a variable focal length. It is usually measured in millimeters.

When you change the focal length, the viewing angle changes. The longer the focal length, the smaller the viewing angle. Conversely, the smaller it is, the larger the viewing angle.

In addition, the optical zoom of the lens is based on changing the focal length, the smaller the focal length, the larger the zoom. By the way, zoom can be easily calculated by dividing the larger value of the focal length by the smaller one.

So, for example, a lens with a focal length of f=3.6~36 mm has a zoom of 10x, and a lens with a focal length of f = 4.1~73.8 mm has a zoom of 18x. The focal length values directly depend on the size of the CCD (after all, this is what determines what size the projected and focused image should be).

You should not chase after too large a range of focal lengths.

There are no miracles, and trying to get a huge zoom with a small lens size will not lead to anything good.

The second value usually given for lenses is aperture ratio. It is calculated according to a simple formula, if the diameter of the hole through which the light passes is divided by the focal length, then we get a value equal to one divided by the relative aperture: D / f = 1 / F The correct marking of the relative aperture looks like, for example, 1: 1.8 or 1 :3.0. But often they write easier, F=1.8 or F=3.0.

As you can see, the relative aperture can change both with a change in the focal length and with a change in the diameter of the lens. The diameter of the lens itself, of course, no one changes, this is the aperture. The diaphragm usually consists of several metal plates that, moving in a spiral, can change the diameter of the hole in the middle.

It is clearly visible on the lenses of old cameras, but you should not even try to see it in new video cameras. On new cameras, the aperture (if there is one at all) is hidden deep inside, and it is not visible from the outside. It is adjusted automatically, depending on the lighting, and the user can only influence it by adjusting the exposure.

The smaller the Aperture (F) value, the better the lens transmits light, which means that you can expect better results from it in low light conditions. A high F value indicates a large depth of field. It should be borne in mind that the best lens can be hopelessly ruined by a bad CCD.

However, such combinations are not found among serial cameras. Relative aperture and focal lengths, although important, are by no means the only parameters that determine the quality of a lens. With a small lens diameter, characteristic of amateur video cameras, and a sufficiently large range of focal lengths, it is almost impossible to avoid various optical distortions (aberations).

Publication: video-minidv.blogspot.com

We recommend interesting articles Section video art:

▪ Useful tips for using miniDV cassettes

▪ MTS file format of modern camcorders

▪ wedding video editing

See other articles Section video art.

Read and write useful comments on this article.

<< Back

Latest news of science and technology, new electronics:

Artificial leather for touch emulation 15.04.2024

In a modern technology world where distance is becoming increasingly commonplace, maintaining connection and a sense of closeness is important. Recent developments in artificial skin by German scientists from Saarland University represent a new era in virtual interactions. German researchers from Saarland University have developed ultra-thin films that can transmit the sensation of touch over a distance. This cutting-edge technology provides new opportunities for virtual communication, especially for those who find themselves far from their loved ones. The ultra-thin films developed by the researchers, just 50 micrometers thick, can be integrated into textiles and worn like a second skin. These films act as sensors that recognize tactile signals from mom or dad, and as actuators that transmit these movements to the baby. Parents' touch to the fabric activates sensors that react to pressure and deform the ultra-thin film. This ... >>

Petgugu Global cat litter 15.04.2024

Taking care of pets can often be a challenge, especially when it comes to keeping your home clean. A new interesting solution from the Petgugu Global startup has been presented, which will make life easier for cat owners and help them keep their home perfectly clean and tidy. Startup Petgugu Global has unveiled a unique cat toilet that can automatically flush feces, keeping your home clean and fresh. This innovative device is equipped with various smart sensors that monitor your pet's toilet activity and activate to automatically clean after use. The device connects to the sewer system and ensures efficient waste removal without the need for intervention from the owner. Additionally, the toilet has a large flushable storage capacity, making it ideal for multi-cat households. The Petgugu cat litter bowl is designed for use with water-soluble litters and offers a range of additional ... >>

The attractiveness of caring men 14.04.2024

The stereotype that women prefer "bad boys" has long been widespread. However, recent research conducted by British scientists from Monash University offers a new perspective on this issue. They looked at how women responded to men's emotional responsibility and willingness to help others. The study's findings could change our understanding of what makes men attractive to women. A study conducted by scientists from Monash University leads to new findings about men's attractiveness to women. In the experiment, women were shown photographs of men with brief stories about their behavior in various situations, including their reaction to an encounter with a homeless person. Some of the men ignored the homeless man, while others helped him, such as buying him food. A study found that men who showed empathy and kindness were more attractive to women compared to men who showed empathy and kindness. ... >>

Random news from the Archive

New generation Chevrolet Volt with smart charging system 03.12.2014

Chevrolet at the auto show in Los Angeles (USA) literally lifted the veil of secrecy over the next generation Volt hybrid car, showing a fragment of its frontal part.

The car was presented in blue. Judging by what was shown to the public, the new hybrid will receive a more aggressive appearance compared to the current generation.

In addition, Chevrolet spoke about the "smart" system for recharging the battery pack. The owners of the new "Volta", in particular, will be able to set certain parameters of the recharging process for the "home" network: this can be an operating mode, charging start and end times, etc. The settings will be automatically selected by the car based on GPS coordinates, so that the motorist will not have to install them every time after arriving home.

In addition, the car will receive an informative indication of the charging status. By the color of the backlight, it will be possible to understand whether the process of replenishing energy or the machine is in the delayed start recharging mode.

The new generation hybrid will debut in January 2015 at the North American International Auto Show in Detroit.

Other interesting news:

▪ A camera with a resolution of 400 thousand pixels has been developed

▪ Biologists have grown a fly with dinosaur genes

▪ Mean Well LED drivers with Smart Timer Dimming

▪ Netbook Samsung N310

▪ How to recognize fake lycra

News feed of science and technology, new electronics

Interesting materials of the Free Technical Library:

▪ section of the Antenna website. Article selection

▪ article Knowledge is power. Popular expression

▪ article Why did the Lords of the Admiralty still promote the son of a farmhand, James Cook, to an officer? Detailed answer

▪ Stockrose's paper is pink. Legends, cultivation, methods of application

▪ article Solders and fluxes. Encyclopedia of radio electronics and electrical engineering

▪ article Transmitting sound over the IR channel. Encyclopedia of radio electronics and electrical engineering

Leave your comment on this article:

All languages of this page

Home page | Library | Articles | Website map | Site Reviews