What mode should I use to take pictures with a SLR, and is there a blurred background?

Generally use M (manual) or A (aperture priority) or U (user-defined).

Manual and user's own settings are better. If it is automatic, it is best to use a card machine.

Background blur can be expressed by enlarging the aperture or lengthening the focal length.

Use fixed focus to represent blur.

The typical lens for portrait shooting is 50-135 mm. As long as the aperture of these lenses is greater than 2.8, it will produce a very obvious blur effect of separating the subject from the background. So many portrait photographers always have a 70-200/2.8 lens.

As for the fixed-focus 1.4/ 1.8 aperture lens, its greater advantage is that it has higher speed to cope with flicker-free photography in low light environment. At the same time, the Jiao Wai performance and optical quality of fixed-focus lens are better than that of zoom (but it is not obvious in many cases)

For portrait photography, the lighting system is a key factor that cannot be ignored. It is difficult to shoot with a large aperture of more than 2 in bright environment, so a 70-200 zoom lens is very suitable for portraits.

If you can still take some environmental portraits, you can buy a 24mm or 35mm fixed-focus lens as a match. Of course, the 24-70/2.8 lens is also versatile.

The part where landscape photography and portrait photography overlap more is actually the medium telephoto. If the subject likes the scenery of mountains and seas, then a medium telephoto lens is essential. Generally speaking, the lens of 100 ~ 200mm is more suitable for representing distant mountains and rivers, as well as vast plains and valleys overlooking from a height. In that scene, the wide-angle lens is easy to take in too much irrelevant information, and the subject is too small and lacks tension.

But in some cases, it is necessary to show the immersive landscape photos with super wide angle. At this time, 24mm is the starting point, and more photographers will use the lens of 2118/15.

Finally, add a 50mm lens, which is a particularly good focal length for people who love it, and it is also an easy focal length. However, because the threshold of 50mm is very low and the cost performance is very high, it is recommended to buy one under any circumstances.