I wonder if it's possible to trigger the SB-910 with a D3100 (like with the pop-up flash), it said it support CLS. But I can't figure how. Or if there is other build in way.
Nikon D3XXX/5XXX does not support CLS unless using another flash such as a SB700/900/910/5000. In order to trigger the flash you will need to set to remote/su4, adjust lighting manually.
