There were many similarities between the way that blacks experienced life in the South during these two eras, but there are major differences as well.
The major similarity is that blacks were economically dependent on whites and were kept subordinate to them in both eras. In 1850, blacks were explicitly dependent because they were slaves. But the sharecropping system of the 1890s worked to keep black sharecroppers indebted to and dependent on whites as well. In both eras, blacks had to show deference to whites in all ways and in both eras a lack of deference could have severe consequences (including physical beatings or even death).
There is a huge difference, though. Blacks in the 1890s were not literally owned by the whites. This is a huge difference because it allowed blacks to, for example, know that neither they nor their families could be sold away from one another. They were able to officially marry and were free from the previous worry of slave women being forced to sleep with their masters. In these very important ways, blacks had much less to worry about during the 1890s.