How to shoot Nikon d90 in an environment with strong contrast before and after shooting light? Ask a master for advice?

In this case, a flash should be used to form the foreground. You don't need a flash, you can only ignore the background and make the foreground exposed properly. Blur the background with a large aperture, invisible, invisible. Otherwise, compromise exposure can be considered (that is, try to expose dark places and bright places in a dynamic range), but the effect is definitely not as good as others. And when the contrast is too big, you may not be able to compromise.

2.

The best way to deal with these shadows is to fill the light with a flash. Maybe your flash is not good, but if you fill the light, you can use the top flash. Generally, the flash compensation effect is-1.6ev ~-1.3ev. You can also try to use a polarizer to eliminate some highlights. In addition, the use of shadows, composition, and the use of facial shadows give a three-dimensional impression.

3.

After all, dynamic D illumination is a kind of built-in PS, which can increase the homomorphism range. However, after increasing the dynamic range, the original dark noise is still more than normal exposure. If it is used, it is aimed at the situation of strong light contrast. According to the situation of bright and dark places, as far as possible, both bright and dark places should be exposed within the tolerance range. If the tolerance range is not enough, at least the exposure should be within the dynamic range. Then adjust the photo to the appropriate brightness through dynamic D-Lighting.