|Off Camera Flash Setup with Nikon Speedlights|
ISO, Shutter Speed, Aperture and +/-
There are a few things that will affect you getting a proper exposure. Let's set each of these on a Nikon so that everything will work.
ISO - Be sure you are not using Auto ISO. Start with the lowest ISO and adjust up for various reasons. You may want to up the ISO to help open up the background for example.
Go into the menu and set the Auto FP high sync speed to 250*. Auto FP High Speed Sync is a flash mode used for fill-flash photography under brightly lit conditions. When it is set you will be able to shoot faster than 1/250 sync speed and do this only with your Nikon Speedlight system.
Set the flash setting to Slow Sync or Rear Sync. I prefer Slow Sync for most everything. This will fire the flash and if needed the shutter may stay open for longer, but this will freeze the subject when you push the shutter. If you choose Rear Sync then the flash will fire at the end of the shutter cycle. You may not know when the flash fires using this setting.
Please refer to the older posts on this to know how to control how much light is on the subject and how to control the background.
Ambient Light and Flash Combined
Flash Over Exposing
First be sure to turn the flash as far down as possible. Using the SU-800 it will go to -3 Stops.
If you still are over exposed it is usually your ISO is set too high. Lower your ISO setting.
Background is too dark
Crank up the ISO and double check to be sure you have Slow Sync chosen or you will be syncing at the lowest shutter speed of about 1/60. You may need to be slower.Background is controlled by the camera +/- exposure compensation dial as well as ISO.
Flash is too bright or dark
Remember the control for this is the SU-800 or the master setting in the pop up flash on the models having this control.