setting bulb
 

Hi there. ive got a d90 nikon. i bought a 10 stop nd filter. i wanted long exposures in day light. but when i press the shutter, it doesnt always just stay open, it just fires as normal, resulting in a black exposure, any ideas Phil

Phil, page 85 in the manual will tell you what to do. You need to have the camera set to Manual and hold the shutter-release button down or use a remote cord or remote control like the ML-L3 (it's basic but only costs around £10)

cheers for that, i may have had it on aperture setting Phil

As the acronym goes RTFM! (Read The Flaming (?) Manual.:p

[QUOTE=focusphil;82820]cheers for that, i may have had it on aperture setting Phil[/QUOTE]
I have a graduated neutral density filter that goes up to ten stops. I've had success with setting it on Aperture priority, and using a fairly wide aperture. The camera sets the amount of time up to a limit of 30 seconds.

An intervalometer is also a useful asset as you can put the camera on Manual, and dial in the number of seconds you want. Some cameras - like my Nikon D5100 - have an intervalometer built in. They can be purchased separately, quite cheaply, too.