Nikon D50 - Manual lens - SB-400

I have been using my D50 with a SB-400 for no problem for quite some time now,

but just recently I attached an older prime, full manual lens with my SB-400

and the SB-400 doesnt want to fire. Again, i have not had any problems using

this lens in the past, but without the SB-400. I have used the on camera flash

and lens without a problem. I set my camera to manual mode, manual focus, and

set the flash mode to manual but the little flash icon on the viewfinder LCD

and on the top LCD still blinks. Is there some other setting I need to change

to get this flash to work with my manual lens?

The manual that came with the flash reads nothing about using it with manual lenses. Are there any options for me? Or am I just going to have to live with the fact that i cannot use this falsh with this lens?

Thanks

When the SB-400 was released, Nikon said that the only camera that would function

correctly with this unit while set to M was the D40. It's likely that the D40X later inherited this

ability. I'm not sure about the newer cameras, like the D300.

So it's the fact that you are shooting in M mode on your D50 that is causing the issue here -

manual mode on a D50 won't work with the SB-400, regardless of lens. Of course, with this

older prime, you have no choice but to shoot M. The conclusion is that you'll have to rely on

the onboard flash or another flash unit if you use this lens with the D50 and the SB-400.