Raw field disappear

I have written a logstash conf filefor reading logs. If I use the default index, that is logstash-*, I could see .raw field in kibana. However, if I create a new index in conf file in logstash like

output{
elasticsearch {
hosts => "localhost"
index => "batchjob-*"}
}
Then the new index cant configure .raw field. Is there any resolve ways to solve it? Great Thanks.