What's the difference between Sony A7 and Sony A7R?

Everyone knows that Sony's camera is good, so do you know the difference between Sony camera A7 and A7R? Come and have a look with me.

The difference between Sony A7 and Sony A7R

Sony A7R can quickly and automatically sample and optimize the original 4k signal, and output full HD video of1080p (1920x108050p). In addition, Sony A7R has regional noise reduction technology, which can adjust the noise reduction and sharpening degree according to different positions in the photo, and even with high ISO, a clear and clean picture can be obtained. Sony A7 has the functions of continuous autofocus locking, eye control AF function, selectable focus size and area focusing, and has the capability of 1920x 1080/50p full HD video shooting and 4K HD image output.

Sony A7R is equipped with a 35mm Exmor CMOS image sensor from Quan Huafu, with an effective pixel of about 36.4 million. It has cancelled the optical low-pass filter and built a brand-new BIONZ X image processor, which can quickly process a large amount of image information transmitted by the Exmor CMOS image sensor from Quan Huafu. Sony A7 is equipped with Quan Huafu Exmor CMOS image sensor with an effective pixel of about 24.3 million, and 7 has a brand-new BIONZ X image processor, which has the technology to restore the real image, reduce the diffraction influence and optimize the regional noise reduction function.

Sony A7R adopts a 3.0-inch12.29 megapixel foldable Xtra Fine LCD screen, which can be up by about 90? , dropped by about 45? . The flip screen adopts the old structure before NEX-7, all-metal body. Sony A7 adopts a 3-inch 920,000-pixel rotatable Xtra Fine LCD screen, and the screen can be turned up by 90? , flip down 45? , no touch function. What is the size of Sony A7 126.7? 94.4? 48.2mm, magnesium-aluminum fuselage, camera dustproof and waterproof dual structure.

Imaging principle of SLR camera

In this system, the unique design of the mirror and prism enables the photographer to directly observe the image passing through the lens from the viewfinder.

It can be seen from the structural diagram of a single-lens reflex camera that the light reaches the reflector through the lens and is reflected to the focusing screen above to form an image. Through the eyepiece and pentaprism, we can see the scenery outside in the observation window. The light passes through the lens and is reflected by the reflector to the frosted viewfinder. Through the convex lens and reflected in the pentaprism, the final image appears in the viewfinder. When the shutter is pressed, the mirror moves in the direction indicated by the arrow, and the mirror is lifted to take an image on the CCD, which is consistent with what is seen on the viewfinder screen.

Compared with paraxial cameras, SLR cameras have the advantage that what you see is what you get, and the imaging angle in the viewfinder is the same as the final film. However, compared with paraxial camera, the back focus of SLR camera lens should be able to image at the focal plane of reflector and photosensitive element at the same time, and false focus must be generated before imaging at the focal plane, which makes the structure of SLR camera optical lens more complicated and larger, and the imaging effect is not as direct and transparent as paraxial camera. At the same time reflector? Big volume, big volume.

SLR camera evaluation

superiority

It only has one lens, which is used for taking pictures and framing, so the parallax problem is basically solved. When taking a view, the light emitted by the object is focused by the lens, reflected by the oblique mirror to form an image, and then reflected by the "roof prism" raised at the top. Photographers can observe the scene through the eyepiece, and it is the same image as the scene, which is convenient for framing and focusing. When shooting, the mirror will bounce up immediately, the lens aperture will automatically shrink to a predetermined value, and the shutter will open to make the film sensitive; After exposure, the shutter is closed and the aperture of the mirror and lens is reset at the same time.

Single-lens reflex cameras can be replaced by various wide-angle, medium-focus, telephoto or zoom lenses, and can also be equipped with close-up lenses, telescopic rings or telescopic leather cavities as needed. In short, any scene that can be seen clearly from the viewfinder can be photographed by the camera. A simple single-lens reflex camera using 120 film generally does not need a pentaprism (such as Great Wall DF-4) and can directly focus on the ground glass. Mid-to-high-end single-lens reflex cameras can also be replaced by overlooking viewfinders (such as Zhujiang S-20 1, Nikon F3), so they can also be used for low overhead or inverted viewing just like dual-lens reflex cameras. This is one of the reasons why the single-lens reflex camera gradually replaces the double-lens reflex camera.

Five fatal temptations of DSLR

1. Excellent imaging quality is the first reason why many consumers favor DSLR.

Because the photoreceptor area of DSLR is much larger than that of consumer cameras, and the pixels per inch are relatively greatly reduced, the performance of DSLR far exceeds that of consumer cameras in terms of latitude, resolution and high sensitivity. The size of the photoreceptor is also the last factor that affects the sales of consumer cameras. Manufacturers often use other indicators such as high pixels to distract users. In fact, the size of the photoreceptor is far more important than the number of pixels. The maximum size of the photoreceptor of consumer cameras is only11.7 inch, while the photoreceptor area of SLR is mostly APS-C (23.7mm? 15.6 mm) to full size (36 mm? 24 mm).

2. The shutter of 2.DSLR is a pure mechanical shutter or an electronically controlled mechanical shutter. The shutter has a very short time lag, and it can be imaged after pressing the shutter, which is a sharp weapon for capturing pictures.

The start-up speed of DSLR is only a few hundred milliseconds, and the continuous shooting speed is also very fast. Consumer cameras, on the other hand, are pure electronic shutters, which has a serious shutter lag problem. This weakness can be called the weakness of consumer cameras, so it can shoot still life, but it is not suitable for capturing moving objects? What you often get is not the action when you press the shutter.

3. The framing of the SLR camera is through the lens, which looks very bright, and the picture the user sees is the picture he will take. At the same time, the transparent light makes it easier to observe the focusing effect when focusing.

Consumer cameras take pictures through photoreceptors and LCD, so there will be some errors in the observation of brightness and color, which is not easy to detect, and it is even more difficult to see the picture clearly in the dark. Even if there is an optical viewfinder on a consumer camera, its optical path does not pass through the lens, so there is parallax.

The lens of 4.4. The DSLR can be changed according to the shooting theme. The lens of consumer cameras cannot be replaced, and the lens quality is much worse than that of DSLR.

5.DSLR has many manual functions.

DSLR can easily zoom manually and set shooting parameters manually. , and you can take some special shots (such as shooting fireworks with door B). But many consumer cameras are automatic. Most cameras don't have a manual zoom ring, so they have to zoom automatically by a motor. Because the speed of zooming is slow, many shooting opportunities will be lost. Many people think that automation is better than manual operation, which is really a misunderstanding. Cameras with automatic function but no manual function are often low-end cameras, because the accuracy and speed of automation are far less than that of manual operation.

disadvantaged

The disadvantages of a single-lens reflex camera are:

1, which is bulky and inconvenient to carry.

Because the mirror and pentaprism of SLR camera are essential, the body can't be smaller. In order to ensure the firmness, materials can not be saved, which determines that it can not be more ideal in weight and volume. A huge camera that is too conspicuous will even affect the mood of the subject when shooting humanistic subjects, which is too easy to give people a sense of depression. Carrying is also a problem.

2. Mechanical vibration and noise

When the reflector works and the shutter curtain is opened and closed, most SLR cameras are noisy and cannot be used in some quiet environments. Especially the vibration of reflector, even if there is no external force, its own vibration will affect the image quality. If you want to avoid vibration when shooting night scenes, you should open the reflector for pre-lifting, so as to avoid the picture shaking when the machine vibrates.

3. What you see is what you get.

Because framing is through the lens, although what you see is what you get, framing is also restricted by the lens, and the brightness of the field of vision is greatly affected by the lens. When using a lens with a relatively large maximum aperture, the viewfinder may be brighter, but when using a lens with a relatively small aperture, the field of view will be darker.

4, the operation is complicated

There are too many functional parameters for professional cameras to set by themselves. Although the entry-level SLR has added a lot of fool modes, which has solved the threshold problem of using SLR well, it is obviously a waste for SLR cameras to use only fool modes.

5. A large amount of capital investment in the later period.

Some friends have macro function when using small digital cameras, and usually shoot flowers and plants, but after using SLR, they have to buy a macro lens to realize those. Some manufacturers' SLR bodies are not anti-shake, and anti-shake needs to be realized on the lens. Buying a lens with anti-shake function increases the cost.

6, need to pay special attention to cleaning and maintenance.

It is good to replace the lens, but if you are not careful, there will be dust in the fuselage, which is likely to fall on the photosensitive element. If you forget to clean it, the photos you take will have a lot of dirty spots. Related necessities are also expensive. With a SLR, of course, you need a sturdy tripod, and a set of sturdy domestic tripods costs about 1000 yuan. A good lens should be matched with a good UV mirror. According to the shooting subject and shooting conditions, it is also necessary to equip accessories such as polarizers and reducers. Backpacks should be stronger, too. Good quality backpacks are more expensive.

To sum up the above points, it can be concluded that it is more reasonable to use a small digital camera if the lighting environment is not harsh, if you don't require extremely high image quality, or if you are afraid of affecting the conditions of the subject. As an ordinary photographer, the choice of image quality and portability determines the direction of choosing a camera. In fact, the best camera is the one that suits you best.

Therefore, some foreign journalists picked up cameras with head-up framing and double-image overlapping focusing. They think this camera is small and light, with bright view, quick focus and easy to capture.

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