For some reason my D300 is under exposing everything. I shot an infant yesterday and had to set the camera to 1/50 at F2 and that is inside with a strobe for the main and two SBs for the fill on the white background. At that exposure I should have been blown out. I have checked everything I can think of and it is still underexposing. Any suggestions?? Thanks for any help.
Are you seeing the underexposure just on this shot, or on others too (with or without flash)? I'm assuming you are in Manual exposure mode, but do you have Auto ISO enabled? What are the settings on your strobes/speedlights? Do you have exposure compensation or flash exposure compensation engaged?
No all the shots were underexposed. I am shooting in M but did not have Auto ISO on. I have tried it with Auto ISO on and it will go to the highest ISO I have set . Exposure comp and flash exposure comp are set at zero. The SBs were set at 1/1 SU4 mode and the strobe was at 100. I just went outside and shot white roses directly in the sun camera was set to S at 1/800 F 5.6 ISO 400 that just seems wrong.
Just for giggles, look at the front of the lens and press the Depth of Field Preview button with the Aperture wide open. If the aperture stop down mechanism is closing the aperture more than it should be, you should be able to see it. If the aperture closes with the lens wide open, the stop down mechanism is the cause of your problem. If the aperture doesn't move, I would suspect a shutter speed problem.