Can the SB400 be controlled remotely? I don't think mine can on my 5100...
You can fire any flash remotely with a very cheap slave unit. You wont get any control of course, but its not
difficult to control the lighting by moving the flash back or forward or with filters etc.
The in camera flash would fire the slave unit. The only thing I would check, is if the SB400 doesnt have a
manual setting, is to see if it fires full power on the test button. The only way you can use the SB400 whilst
keeping TTL is for it to be corded. ( as far as I know ). That slave flash I mentioned earlier... I bought one not long
ago on Ebay for £35. Not sure what that is in dollars, but I think thats about 50 dollars.
These can be used also with full TTL when using a Flash with comand mode such as The SB900 etc.