Perplexity's Focus modes and source filtering are the controls that change research quality, not just research speed
The Focus feature narrowing search scope with options including Search, Deep Research, Model Council and Learn step by step is the research intent specification that changes what Perplexity does with your query. A learning-intent query and a research-intent query on the same topic should produce different outputs and the Focus modes are what communicate that intent explicitly.
The @ command for quickly applying specific focus parameters being available mid-conversation is the workflow efficiency that means you do not need to restart to change your research mode. Switching from a broad web search to an academic focus on the same topic within the same conversation preserves the context while changing the source scope.
Deep Research being a Focus mode rather than a separate product is worth understanding as an access point. Using @deep in a query activates the multi-step research mode without leaving the normal Perplexity interface.
For researchers using Perplexity regularly: which Focus mode produces the most consistently useful results for your primary research type and which mode do you find yourself using less than you expected?