How to choose a SLR?

It depends on your budget. Just buy the most expensive one within the largest budget. For general household use, in addition to the entry-level machine D3100 550D, you can consider D90, D7000 60D 7D. These 4 mid-range products must go to Wukesong. Buying cameras at regular places like Photographic Equipment City or Ruiyi, places like Dazhong Suning, is generally 1-2 thousand more expensive than at the Equipment City

The following is a reference

It is worth comparing One of the technical indicators: lens angle of view conversion rate and photoreceptor size

The starting point for discussing this technical detail is how you can obtain a larger angle of view and better photoreceptor performance at the same price. As we all know, under the premise of the same number of pixels, the larger the photoreceptor size, the better the imaging effect (this is also the Achilles heel of consumer-grade DC that cannot surpass DSLR at all).

First of all, we must pay attention to correct the misconception of "lens focal length conversion rate". The focal length of the lens will not change due to the different photoreceptor frames. Only the angle of view will change due to the different photoreceptor frames. Therefore, the lens angle conversion rate is the most accurate statement.

Since the imaging area directly affects the lens angle conversion rate, in this comparison, you only need to pay attention to the lens angle conversion rate to know the difference in photoreceptor area. The lens angle conversion ratios of the five products of Nikon, Samsung, and Sony are all 1.5 times, and the photoreceptor area is the largest. Canon's two products follow closely behind, with a lens angle of view conversion rate of 1.6x and a slightly smaller photoreceptor. The difference from the above five products is not obvious at 1.5x. But the biggest difference from the other seven products is the Olympus E-520. The lens angle conversion rate is 2.0 times, which means it has the smallest photoreceptor area, smallest frame, and smallest field of view (not to mention the 4: 3 ratio).

The second technical indicator worth comparing: the number of autofocus points

Although many users are accustomed to using the central focus point of the autofocus system to focus and then recompose the shot, so You may not care much about the number and distribution of focus points in the entire focusing system, but since modern autofocus cameras provide us with more focus point choices, we should take advantage of this advancement to bring convenience to our shooting. The significance of having more autofocus points is that when you use multi-point autofocus, the camera will help you confirm the focus more quickly and accurately, without the need for you to manually confirm with the central focus point, which is often too late when taking a quick snap. . What's more, if the price is comparable, why not choose a better one?

The third technical indicator worth comparing: Optical viewfinder type

The traditional SLR camera viewfinding method is that after the light enters the lens, it is reflected by the reflector to the focusing screen and enters the five-dimensional viewfinder. The prism enters the eyepiece after secondary reflection from the inner surface of the pentaprism. Pentaprisms made of finely ground high-quality optical glass have very excellent optical performance, very high reflectivity, and very little light loss in the optical path, so the viewing field of view is bright and clear. However, high-quality pentaprisms are expensive and heavy, which increases the cost and weight of the entire camera.

In a pentaprism, there are only two reflective surfaces that actually participate in light steering. Therefore, some manufacturers widely use pentaprisms in low-end digital SLR cameras to simulate the light path of the pentaprism, instead of the pentaprism's light path. Function. Its principle is equivalent to using a pentaprism as a mold, demoulding a shell around its mirror surface, and then coating the two reflective surfaces with a high-reflective layer, replacing the role of the pentaprism. However, the disadvantage of the pentamirror is that its refractive index is poor, which will cause the viewing light to be lost and the light in the viewfinder to be dimmed.

Therefore, the type of viewfinder used is also one of the main specifications to measure the grade of a digital SLR camera. Unfortunately, many review articles did not cover this detail, and the so-called official information from the manufacturers was mostly vague. After verification from many parties, we determined the viewfinder types of all eight products.

There is a price to pay for using a pentaprism. How to choose requires consumers to weigh it - whether they need a brighter viewfinder, lighter weight and cheaper price, this idea is up to consumers themselves.

The fourth technical indicator worth comparing: the performance of the real-time viewfinder

Although using LCD to view the view is not a traditional way of taking pictures, for those who have never used a film camera, But for users who have been exposed to photography with consumer-level cameras (especially compact cameras), using LCD viewfinders is more comfortable than using traditional eyepiece viewfinders. Entry-level SLR cameras incorporate the "Live View" real-time view function of LCD viewfinder. On the one hand, it takes care of the habits of consumer-level camera users, and on the other hand, it provides convenience for viewing in special camera positions where it is inconvenient to use eyepieces.

However, the current live view function is not perfect. On the one hand, the electronic image transmitted by the photoreceptor cannot be more realistic and credible than the light passing through the lens (mainly brightness and color); on the other hand, due to the different light path design, the metering and focusing of real-time view are not advanced. It can be said. This function is a transitional function and cannot be used as a criterion for choosing a digital SLR. Some cameras do not provide this function at all.