In this poster, we describe central aspects of 65 natural information tasks from 23 senior researchers, PhDs, and experienced MSc students from three different university departments of physics. We analyze 1) the main purpose of the information task, 2) which and how many search facets were used to describe the tasks, 3) what semantic categories were used to express the search facets, and 4) retrieval performance. Results show variety in structure and length across task descriptions and task purposes. The results indicate effect of length and, in particular, of task purpose on retrieval performance of different document description levels that should be examined further.