[logback-user] have to cast logger to use logback specific api

Hello: I tried the Helloword1 example that comes with logback and noticed that slf4j's Logger does not have methods such as logger.setLevel that logback provides, in order to use it, I have to cast it to logback's Logger.  I'd need to use those methods in app on the fly instead of use a static config file.  But once I cast it, it means it would be tied to logback and why bother with the slf4j at all? I mean once I do this way, I can not do the deployment time switch to other logging lib. What would be the recommended way to deal with my scenarios? Thanks