What is the function of a large aperture lens? Introduction to the function of a large aperture lens

What is the function of a large aperture lens?

The use of a large aperture requires strong control capabilities, and it is not always locked at the maximum aperture. , it doesn’t mean that the eyes are clear and the eye hairs are gone, the pictures are all good-looking. The loss of image quality at large apertures is very serious, especially edge imaging and vignetting, which are far behind the optimal aperture.

Next, let’s take a look at the explanation of large aperture lenses.

When our equipment has covered the commonly used focal lengths and satisfied daily basic shooting, but when we walk through the display window of the equipment store, open a magazine and see an advertisement, or play with friends around us, The restlessness in your heart will spread out of control. Then, a large-aperture lens will soon or has become a must-have in our photography bag!

Large-aperture lenses mostly refer to lenses of F2.8 and above. Due to limitations in the production process, zoom lenses The maximum aperture is mostly F2.8, and there are also some non-full zoom lenses that can achieve F2.0. Larger apertures mostly appear on fixed-focus lenses. The more common ones are F1.8 and F1.4, but there are also larger F1.0 and F0.95. Of course, some special equipment lenses can achieve F0.7, but the pictures of this kind of lens can only be seen on relevant foreign websites, and they are all used for extreme purposes such as military and space.

Large-aperture lenses are mostly positioned as professional-grade lenses, and their imaging, workmanship, and materials are all superior to ordinary lenses. Particularly expensive technologies and materials, such as nanocrystalline coatings and fluorite lenses, are used generously on this type of lens. A large number of aspherical lenses, ultra-low dispersion lenses, etc. are added in quantities that are unmatched by other lenses. . And the price of such a lens is naturally professional level. New zoom lenses with constant F2.8 can easily cost over 10,000 yuan, and new fixed-focus lenses with F1.4 are difficult to find for less than 10,000 yuan. This is not only because of the workmanship and materials used, but also because of the difficulty of the production process. The larger the aperture, the more complex the production process, and the more expensive the price. The design process of lenses with unconventional focal lengths will be several times more difficult, so even if the aperture is not particularly large, the price will be staggering.

Of course, the 50mm standard lens is an outlier among them, with large apertures of F1.8 and F1.4. However, its production process is mature and its structure is simple, so it is extremely compact and its price is only equivalent to an entry-level kit. , many photography masters during World War II, only this one shot left behind a masterpiece that will be passed down from generation to generation.

The biggest difference between a large aperture lens and an ordinary lens is the amount of light transmitted and the depth of field. The larger the aperture, the greater the amount of light. When in low light, a lens with an aperture of F5.6 may take 1/8 second, while with an aperture of F1.4, shooting can be achieved in 1/125 second. The amount of light transmitted is reflected in the aperture values: F1.0, F1.4, F2, F4, F5.6, F8, F11, F16, F22, F32. The smaller number after F is a larger aperture, and the F value For every one stop, the shutter speed also increases by one stop, so the most direct benefit of a large aperture lens in terms of control is obvious.

Depth of field is a relatively deep knowledge. Early cameras had depth of field prediction, and now some new high-end cameras should retain this function. The so-called depth of field refers to the clear range in front and back with the focus point as the center. The depth of field is affected by the focal length, focusing distance and aperture size, the most obvious of which is the aperture. Especially at the telephoto end, the size of one aperture can make a huge difference in depth of field. When shooting with a large aperture, the subject in focus is clear, and the distant scenery in front and behind is blurred, making it easy to highlight the subject. On the contrary, if the clear range of the subject's front and rear is too large, it will easily distract attention from the too cluttered front and rear backgrounds.

The large aperture lens on the upper level of technology will provide dreamlike blur in addition to the clear subject, while the larger aperture above F1.0 will provide more than just a creamy bokeh. In a sense, it can be said that it is already another visual world.

Of course, using a large aperture requires extremely strong control capabilities. It is not always locked on the maximum aperture, nor is it a picture of clear eyes and blurred eye hairs. They are all good-looking. The loss of image quality at large apertures is very serious, especially edge imaging and vignetting, which are far behind the optimal aperture.

When shooting with a large aperture, it is also a strict test for the body's focusing system. Entry-level cameras will be somewhat unable to deal with apertures above F2.8. At this time, try to use the center focus point, use F1. When the aperture is 4 or larger, even if it is a professional-level camera, you cannot completely trust the autofocus. You need to pay more attention to the viewfinder and playback, because the depth of field is too shallow and the focus is slightly off, which may cause inaccurate focus.

The size and caliber of the large-aperture lens should also be mentioned. In addition to the 50mm lens, other 135 series large-aperture lenses are very heavy. The calibers are often 72mm, 77mm, and the large-aperture fixed focus at the telephoto end. The aperture will reach an astonishing 100mm or more. Be mentally prepared for considerable additional expenses such as weights and UV lenses. However, some fixed-focus lenses with half-stop aperture and zoom lenses with one-stop smaller aperture have entered the market at relatively low prices.

A large aperture lens can provide you with a more reliable shutter speed under limited light, and can bring you great changes in light and shadow without requiring extremely high lighting skills. It can also be used in Make your subject clearly visible against the cluttered background. Its image quality, feel, and control will all bring you greater photography pleasure. A lens with a large aperture is a beautiful scenery on the long photography road, and it may also be a huge surprise.

The above is an introduction to the function of a large aperture lens. I hope it will be helpful to you!