How to learn to draw a portrait:
Using a camera and video equipment 
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Using a camera and video equipment
The camera will provide invaluable help, it can shoot scenes and figures that you cannot draw from life due to bad weather and lack of time. Try to take a series of shots, so that later, returning home, choose the most successful ones. In addition, you can combine them with elements from other photos.
Photography work
Working on photographs is a great way to build a confident hand. On the flat surface of the photograph, one can clearly see how the various parts of the body relate to each other; they will help you understand this relationship.
Slave copying of a photo will not lead to success - it is wiser to develop your creative skills. For example, you can give the image a contrast by translating the vast tonal range of the photograph into black and white. You can also highlight or darken individual places, as well as change the position of the light source.
You can also recompose the photo. If you want to do this, you can add or remove some people, change their facial expression or even your hair! With such a rearrangement, it is useful to work not with one, but with several shots.
Before you take up the drawing, carefully consider the figures in the photograph. At the same time, pay attention not only to the shape of the depicted faces themselves. but also to the space between them and around them. This will help you keep the correct proportions in your drawing before you add tone and detail. Never proceed to the final finishing of a drawing if you are not sure that the proportions and shapes of the people are conveyed correctly.