What parameters determine the quality of a camera?

Explanation of several key indicators of digital cameras

a. Aperture

It is represented by the f value. Since it is a reciprocal relationship, the greater the f value, the The smaller the aperture. The maximum aperture of general digital cameras is 2.0, and some models are 1.8 (Olympus C-4040ZOOM).

To put it simply, the larger the aperture, the greater the amount of light that enters. The advantage of this is that in low-light environments, a relatively high shutter speed can be maintained without the need for other auxiliary methods.

Another benefit of a large aperture is that it can achieve a shallower depth of field. Simply put, it can make things a certain distance behind the subject blur better, which is generally more beneficial when taking close-ups. So when choosing, try to choose one with a larger maximum aperture. The minimum aperture is usually 8.0, and occasionally it is 11 (Panasonic/Leica DMC-LC1). This value is not very different for most cameras. The price of DMC-LC1 is also close to or exceeds the price of entry-level SLRs, so there is not much room for choice.

b. Shutter

Simply put, the shutter is a device used to determine the length of time the light enters. Generally speaking, the wider the range, the better, but in consumer DC, it will not be too large, especially the highest shutter speed. Currently, a shutter speed exceeding 1/2000 seconds is generally only available on high-end machines, so when choosing, you should pay attention to the slowest speed. , it is best to have a B door, which means you can decide the exposure time yourself, and many models also have it.

c. CCD size

We can see that the CCD size is marked in many introductions. Simply put, the CCD size is the size of the photosensitive chip. Generally, bigger is better. For example, 2/3 is better than 1/1.8, and 1/1.8 is better than 1/2.5. Theoretically, under the same pixels, the larger the CCD size, the less noise will be generated. This is reflected in the purchase of cameras. For example, they are both 5 million pixel cameras. One uses a 2/3 CCD, and the other uses a 1 /1.8 camera, our priority is the 2/3 model.

d. Optical zoom

Generally speaking, optical zoom is very different from digital zoom. Strictly speaking, digital zoom has little practical value. You should pay attention to the difference when purchasing a camera. The target is digital zoom or optical zoom. The emergence of optical zoom lenses was actually born out of the concept of having one lens that can cover the world. Simply put, it is for convenience and a wide range of applications. However, the structure of an optical zoom lens is usually very complex, with a large number of lenses. When light enters the camera, the more lens lenses it produces, the more times it is refracted, which affects the image quality. Therefore, in general, zoom lenses of the same level are Not as good as a fixed focus lens. However, when ordinary users are purchasing, they actually have very little room for choice in this regard, because it is of little significance to seriously discuss imaging quality on general consumer-grade DCs. Generally, high-power telephoto cameras are also high-end cameras, so they won’t be too bad, so you can choose as many options as possible.

e. Pixels

Pixels play a decisive role in the final printing size. Generally, the printing resolution requirement is about 240dpi. What is the concept of this? Here is a simple algorithm. For example, the maximum resolution of a 5-megapixel camera is generally 2,560 x 1,920, and 2560/240 is approximately equal to 10.6. That is to say, a 5-megapixel camera can achieve a maximum length of 10 inch photo. Therefore, before purchasing a camera, use this formula to calculate according to your own needs and find a balance between price and demand. But how to choose DC with the same pixel level? I mentioned the size of the CCD before. This size is a key indicator at this time. Give priority to the CCD with a larger size!

f, ISO value

ISO means sensitivity. The higher the sensitivity, the faster you can detect light. Therefore, in film, high ISO film is also called high-speed film. High ISO is suitable for use in low-light environments, such as taking indoor family photos, night scenes, etc. However, the problem caused by higher sensitivity is that the graininess increases, and the lower the ISO value, the more delicate the picture will be. In DC, low ISO values ??are relatively more practical, while high ISO values ??have poor practical value in DC at this stage, because the picture displayed by high ISO in DC is not just more grainy like traditional film, but There are a lot of colorful noise, which seriously affects the output picture. Basically, it can be said that in ordinary DC (to distinguish it from digital SLR), there is no need to use an ISO higher than 200 (except for Fuji machines). A few The picture performance of high-end machines is better, but in general, it is best not to use it. Therefore, when it comes to the choice of DC, the key selection point of ISO value is the lowest ISO value. For example, Canon's DC generally achieves 50, so it is generally felt that the picture produced by Canon's home DC is more delicate. However, this does not mean that you must choose Canon. Many machines have very good pictures at ISO100, such as Nikon's 5700.

Digital cameras have many functional operations, and imaging effects and operating performance are the most important judgment indicators. During the evaluation process, appearance design, operating characteristics, image quality, etc. are all subjective evaluations. We Use quantitative scoring standards as much as possible to show the performance characteristics of different products, and use the principle of horizontal comparison in a unified manner to treat each product fairly. In addition, we also use software to detect the noise in photos taken by digital cameras under long-term exposure conditions to measure the noise reduction function of the CCD.

Appearance design

Based on the experience of the evaluation engineer, the aesthetics of the overall shape and the display effect of the LCD screen are judged from a visual perspective, and the chassis is determined based on the feel and ordinary operations. The quality of materials and workmanship used, the reasonable distribution of buttons, and the overall score in this item externally reflect the advantages and disadvantages of the industrial styling of the digital camera.

Lens quality

We judge the quality of the lens through the manufacturer of the digital camera lens and the technology used, from hard indicators: aperture, focal length range, to optical and digital zoom multiples , the total score of this item can measure the optical performance of the digital camera.

Menu system

In the process of function adjustment, the design of the menu is very important. We judge it from the strength of the function settings, the convenience of operation, and whether there are Chinese menus and other items. Rating, the total score of this item can judge the perfection of the digital camera in terms of functional design.

Operational performance

From the perspective of actual use, the digital camera is scored on the comfort of hand, the user-friendliness of functional operations, and the response speed of the camera. The total score for this item is It can reflect the considerateness of digital cameras for photographers.

Accessories and Services

In the configuration and service test items, we refer to the quality of random accessories, such as memory card size, battery type, whether the instructions are complete, the application experience of the software system, and After-sales service is scored. The total score of this item can reflect the technological maturity of the camera and the comprehensive service capabilities of the manufacturer.

Image quality

We took real shots of each camera under the most common shooting conditions. The camera was set to the maximum resolution and highest quality. By shooting portraits and macro , scenery, night scene, sports and other scenes, compare the color, clarity, purity and other aspects of digital photos. The total score of this item can reflect the overall imaging quality of the digital camera lens and CCD

I hope it will be helpful to you can help.