Excuse me, what are medium format and large format cameras?

Generally, cameras with a film size of 4X5 (that is, 97mmX 120mm) are collectively called large-format cameras. Large format photography is the symbol of professional photographers who are pursuing high-quality pictures in the world at present, and it is a common professional equipment for advertising photography and landscape photography. The technical difficulty is great, and the comprehensive requirements for photographers are high, so the success rate is low. In the eyes of landscape photographers who pursue high quality, large format cameras are their first choice.

On April 22nd, the first large-format photography exhibition in Sichuan was held in Chengdu. * * * Twenty-five photographers participated in this exhibition, including famous photographers from China, experienced photographers, advertising photographers and novices who haven't been filming for a long time. They range from the chairman, director and boss of the Photographers Association to freelance photographers and senior enthusiasts. Whether they buy cameras or make their own cameras, they all have a belief that a good photographic work needs art and technology to have an impact.

Therefore, the minimum film size for this exhibition is 6cm× 12cm. In order to ensure the quality of the exhibits, all of them are made by digital amplification of reversal films. This is the first high-quality photography exhibition in Sichuan, and it is also a repositioning of Sichuan photographers to challenge themselves and move towards the international market.

This exhibition will arouse people's re-understanding of photography art; What will show you is a beautiful picture shot by a traditional professional camera and digitally amplified by a high-tech laser.

What is a large format camera?

Large format camera The structure of large format camera is very simple, but it is quite complicated to operate, especially the camera's tilt, offset and exposure skills are not easy to master.

The lens of a large-format camera is basically different from that of small and medium-sized cameras such as 120 and 135. The lens of small and medium format camera needs high brightness, high resolution and considerable contrast ability, so as to ensure that the camera can avoid vibration as soon as possible in low light environment and ensure the image quality when shooting quickly. But for a large format camera that can shift, tilt and swing, this problem is not the most important, but the lens angle is the key. Because it determines whether the photographer can effectively play the shift function provided by the large-format camera. The larger the lens viewing angle and the larger the image circle, the better the axis shifting characteristics of the large format camera.

The lens angle of view is 100. ~ 105。 , mainly used in architecture and photography. Common lenses are Shannon W (65 mm- 155 RAM), Ni-Kohl SW (65 mm- 150 mm) and Fuji SW(65nun- 125ram). The standard viewing angle of the lens is 70. 80。 The lens is suitable for medium and long distances.

Shooting theme. Commonly used are Sinalong -S( 135mm-480mm), Sinalong -WS( 150mm-300mm) and Nicole-W lens (105mm-240mmX lens, with a smaller viewing angle of 50. Left and right, the advantage of the lens is the high-definition resolution when shooting at close range. For example, Marco— Sinaron and Apo-Sinaron lenses have been specially corrected, and the effect is very remarkable in macro photography.

For a large format camera, besides the basic indicators such as resolution and sharpness, the important criterion to measure whether a lens is excellent is the angle of view. For example, the viewing angle of Shannon SW lens is increased to 72. Standard lens, so the viewing angle is only 53. The displacement distance of the standard lens is larger.

The lens characteristics of various large-format cameras are different, and sometimes they are not completely limited to the advantage of field of view. For example, macro Sinaron lens and similar macro lenses of other brands are characterized by outstanding close-range photography effect and excellent field curvature correction. For this kind of professional lens, unless otherwise required, there is no need to use the field of vision to measure the pros and cons.

When using a large format camera, a key problem is to solve the problem of light interference. Such as astigmatism caused by bright parts (such as backlight), strong light on the subject, etc. Using a leather hood can eliminate a lot of astigmatism.

Light, this is a very important link. Some cameras are produced, and one company produces a hood frame with four adjustable hoods, which can accurately control and adjust the position of the hood frame. As long as the photographer carefully observes the occlusion in front of the lens through the focusing screen, the lJF occlusion frame can be maintained, and fi will cut off the corners of the focusing screen. In addition, the glare shared by the lenses is also light interference, which is also a factor affecting the imaging quality. In the design of high-quality lenses, each lens is coated, which greatly reduces glare and improves transmittance. At present, the glare coefficient of most lenses is only between 2% and 3%, while that of some old lenses is as high as 5%- 10%. Also note that if the lens surface is not clean or the protective film is scratched, it will also increase astigmatism. We often ignore these details that damage the image quality, but they are all factors that seriously endanger the image quality.

In large format cameras, telephoto lenses are rarely used, not only because they are expensive and not available to every professional photographer, but also because telephoto lenses are not too long compared with D 135 cameras. For example, a 600mm lens installed on an 8×lO-inch camera is only equivalent to a 90mm lens range on a 135 camera. Usually, a large camera is close to the camera, supported by a stable tripod or other special equipment, and can take pictures and compose pictures leisurely. Different from the 35 mm camera, it often relies on a long lens to draw the subject closer, so as to make the picture as full as possible and fully ensure the use of film. Large cameras can use short focal length lenses to fill the lens range calmly, and can also ensure a larger lens image field, which is helpful for the displacement and swing of ten cameras. I think this may be the reason why everyone makes large, medium and small cameras respectively. Small cameras sacrifice the "high" quality of big cameras; Large cameras don't have the "flexibility" of small cameras to shoot quickly.

120 and 135 camera lens, which is better or worse? I believe that most beginners will misunderstand that the imaging quality of the big camera is the highest, because the huge street sign advertising pictures have shown people the special charm of the big camera. On the contrary, if the lens is evaluated by the unit area of the presented image, the lens quality of the large format camera is the lowest, but the picture it takes is much higher than that of the general camera, mainly because the imaging is large and the magnification of the final picture is small. As far as resolution is concerned, the lens quality of large format camera is not as good as that of medium format camera, and that of 120 camera is not as good as that of 135 camera. The lens of 120 camera is used in 135 camera. Although only a small part of the lens center is used and good uniformity is obtained, theoretically, the resolution of the center of the picture should not be better than that of the 135 lens of the same level.

Three reasons why landscape photographers choose large-format cameras

1. The 4×5 loose-leaf film area of large format camera is 135 film area 13.5 times; It is 3.7 times the area of 120 film (6×6). For making large or huge photos, only large negatives can achieve fine particles and true texture.

2. The frame and lens of the large format camera slide along the monorail track or folding bottom plate, and the telescopic leather cavity can be adjusted to achieve the gathering effect, adjust the correction angle, and make the plane distribution clear, showing the characteristics of horizontal and vertical.

3. In the grand shooting of majestic peaks, grasslands, lakes, colorful forests and other scenes, the distance of the theme is clear and natural, which accords with natural perspective and is better than eye perspective.