The difference between SLR and focal plane

The difference between SLR and focal plane

1, front-end caliber.

The spiral filter used in the lens of SLR camera is different from the aperture at the front end of the bayonet hood, but the focal plane needs the hood to block stray light, and a square filter is installed, and the apron, hood ring or bayonet behind the hood must be close to the front end of the lens, so the front end of a group of lenses is often the same aperture, so it is time-saving and labor-saving to replace the focal plane.

2, internal and external zoom.

Many SLR cameras use external zoom, and the lens barrel expands and contracts when zooming. On the focal plane, contact-following focusing gear ring, hood barrel and filter are used, which is not suitable for telescopic lens barrel. Therefore, the displacement of the lens group must be completely realized inside the lens, and no trace can be seen outside, so internal zoom is usually used. Moreover, the focal plane often adopts focus chasing and focus shifting, which needs to solve the respiratory effects of the lens, so the design of floating lens group is adopted.

3. Focus/aperture ring and clamping teeth.

The positions of the focusing gear ring and the aperture gear ring of each focal section in a group of focal planes are matched with each other, and it is not necessary to adjust the position of the follow-up focus or the three-axis driving motor when replacing the lens, which saves time and labor. SLR camera lens usually has no toothed ring used with the follow focus system, and the focusing and aperture rings are textured designs, which are convenient for operators to hold.

4. control.

The focal plane emphasizes more accurate focusing and smoother control than the SLR lens, so the focal plane has a large focus ring stroke and a thin aperture ring, and adopts a segmented aperture design.

5. Aperture value.

The aperture index of the focal plane is different from the F used by the SLR lens, and T is used for marking, for example, CN-E24MM T 1.5LF ... That is to say, it is not only calculated by a simple formula such as the F aperture value, but the actual light input marked by strict testing, and the deviation is much smaller than the F aperture value.

How to choose the right SLR lens

Generally speaking, if you want to have a large aperture with a zoom lens, you have to pay a very expensive price, and you can easily buy a "roast goose" large aperture lens with "cabbage price". First of all, the larger the aperture, the more light is collected by the zoom lens with smaller aperture, which can easily create the effect of shallow depth of field. At night or in indoor low light environment, you can take the desired photos without increasing the sensitivity (ISO). In addition, because the components of the fixed-focus lens can be made smaller than the zoom lens, it will be very light. At the same time, because there is no zoom "convenience", you need to shoot by your own actions, which can help you seriously think about composition. Coupled with the pure structure of fixed-focus lens, the quality is often higher than that of zoom lens, and the price is reasonable. Who can not love it?

Next, I will introduce the three most common focal lengths of fixed-focus lenses: 35mm, 50mm and 85mm.

35mm fixed-focus lens ――EF 35mm f/ 1.4L USM

35mm is a famous humanistic wide angle, and it is also suitable for scenery and group portraits, even portraits. It can give photographers enough space to compose pictures on the street, and it can shoot a wide range, and it can shoot people and most of the surrounding environment. Moreover, it has a slightly wide angle of view and is favored by many street photographers or news photographers. Therefore, some people think that the picture taken with 35mm lens has more "visual impact" than the standard and portrait fixed-focus lens.

50 mm fixed-focus lens-AF-S Nikkor 50 mm f/ 1.8 g

50mm fixed focus lens should be the easiest lens for beginners to use. The famous photographer Bresson also likes to take pictures with a 50 mm lens and Leica. He thinks that the lens is like an extension of the eye, and he thinks that 50mm is the focal length of the human eye. If you use a lens with the same focal length, you can "what you see is what you get". What you see through the observation window with 50mm is equivalent to what you see with the naked eye at present. When you need a quick composition, you can fantasize about the picture you need in your mind. This inexpensive Nikon fixed focus has also been dubbed "the essence of human optics" by insiders.

Expansion: Introduction of SLR lens knowledge

Shutter: Compared with ordinary digital cameras, the most direct change for beginners is to constantly adjust the shutter, adjust the light input of photos through the shutter, and then make a reasonable choice according to the shooting environment and experience. When getting started, you can choose automatic or P mode, take photos first, then check the photo parameters, and then change the shutter through M mode or AVTV. Generally, dark photos will be devalued, while bright photos will be added.

Introductory knowledge ISO: When shooting under special light, it is not enough to simply control the shutter. Setting ISO reasonably will give people more choices. Generally speaking, the lower the ISO value, the better the photo quality, and the less noise, while the higher ISO value is generally used in poor light, or in order to ensure the clarity of the subject when shooting moving objects, so you must learn the constant changes of ISO when getting started.

Introductory knowledge aperture: through the reasonable choice of aperture, a photo can be realistic and layered. When shooting portraits or still life, people or things need to be highlighted, and the background needs to be blurred with a large aperture. General scenery needs to accommodate more information, and multi-level scenes such as front, middle and back need to be recorded in photos with small apertures. The intuitive number of aperture is f value. The smaller the f value, the larger the aperture and the higher the external blur of the subject. The larger the F value, the smaller the aperture, and the better the layering in the landscape.

At the beginning of knowledge, you can skillfully use the above three kinds to take clear and satisfactory photos. Beginner photographers can learn to take clear, bright and outstanding photos. With more and more knowledge of light and shadow photography, ordinary SLR beginners will experience: recording more, taking photos at will, being picky about photos, taking photos for what, and how to get the desired effect. Language organization may not be able to express clearly, and more words will be recorded later.

Parameter method of photography skills: beginners need to have a familiar process with the photo parameters, those environments need to know the corresponding ISO, and the shutter value needs to be adjusted in time after looking back at the photos. Generally, beginners of SLR usually adjust the shutter in time by shooting first. The simplest parameter acquisition is automatic shooting, or a photographer is directly around to show how to set it.

The level of photography skills: it is the basic skill to ensure that you are horizontal and vertical when shooting introductory photography. Although it is a bit dull, it is very helpful to develop habits, to familiarize yourself with the weight of the fuselage, and to gradually familiarize yourself with the functions of SLR cameras.

Photography skills composition and light and shadow: Good photos have either event value or communication and ideological integration, and then they should start from the perspective of light and shadow, and prepare from the knowledge of composition. Introduction to photography needs to start with some basic attempts, which is conducive to a better understanding of photography.

The ultimate goal of novice photography is to get the pleasure and motivation of progress. Happy shooting and shooting are more and more liked by themselves and more people. Stick to shooting, summarize the advantages and disadvantages of classified photography, and then be more prepared to capture the current skills. Enjoying unprofessionalism is the key.