you can ignore some files using the --ignore-paths option of git svn:

 --ignore-paths=<regex>
               This allows one to specify a Perl regular expression that will
               cause skipping of all matching paths from checkout from SVN.
               The --ignore-paths option should match for every fetch
               (including automatic fetches due to clone, dcommit, rebase,
               etc) on a given repository.

                   config key: svn-remote.<name>.ignore-paths

               If the ignore-paths config key is set and the command line
               option is also given, both regular expressions will be used.

               Examples:

               Skip "doc*" directory for every fetch

                       --ignore-paths="^doc"

               Skip "branches" and "tags" of first level directories

                       --ignore-paths="^[^/]+/(?:branches|tags)"