Some rookie questions about photography ~ ~

1, why do cameras use convex lenses now? I know the principle of convex mirror imaging, but why not use flat mirror? Such that the image will not be inverted)

Flat mirrors can't image. With a flat mirror, everything comes out with astigmatism.

2. How to deal with "the distance between me and the object being photographed is very clear, but the depth of field behind the object being photographed is very vague?" )

This so-called clear boundary is not very neatly determined in real shooting, but also has a gradual process. Now all cameras have the function of depth of field prediction. Just adjust the aperture priority and appropriate focal length, start the depth of field prediction, and adjust the aperture at the same time to see if the actual effect is appropriate.

3. Assuming the distance is 0-100m, I want to take a clear picture of the objects at 30m and 70m, but blur the objects at 0-30m, 30-70m and 70m to100m. What should I do?

Take a long-distance shot with a telephoto lens and adjust the aperture to a suitable level. Digital cameras can shoot the effect first, or directly predict the effect with the depth of field.

4. Do ordinary people have a small aperture and a large depth of field? What about the shutter?

People in the photo studio have a big flash, so the shutter speed is basically certain. If you are outdoors, it is not difficult to ensure a speed of 250th of a second with an aperture of 1 1. Generally speaking, the imaging quality under ISO400 is good.

5. I don't know much about the parameters of the lens. Who can give me an example to analyze?

For example: EF28-300L usm is. EF Canon original lens logo, 28-300 zoom range, L professional lens logo, usm ultrasonic motor, is an anti-shake logo.

I want to buy a SLR camera, which is more suitable for me as a photographer? Please recommend it for me (give me an approximate price, and you'd better give reasons for your recommendation)

Canon's 450D kit with anti-shake lens costs about 4,600 yuan, and Nikon's d60 kit costs about 3,580 yuan, with complete functions and good imaging quality.

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1, I know that "Quan Huafu means that the area of CCD/CMOS of a digital camera is as large as that of the film with the same specification (i.e. 36×24mm)". The question is, isn't film used now? How can we compare with it? What are the advantages and disadvantages of the whole picture?

In the film era, enthusiasts have a large number of excellent lenses, and the technology of manufacturers to produce film-sized lenses is relatively mature. Another advantage is that you can get better image quality, because the photosensitive area is large, and the image quality is much better than that of aps machine under the same pixel condition.

2. How is the focal length calculated?

The so-called focal length is theoretically the distance from the lens to the focal plane. Specific to the current lens, because the design is lighter, it is necessary to use multiple groups of lenses to improve the refraction of light. The actual lens length is different from the focal length.