I have a D40x with a AF-S DX ED 18-55 G II lens, which keeps on taking dark to black photo's on Auto, no matter what the lighting conditions, flash used or otherwise.
I have worked out that the camera is shutting the aperture right down underexposing the shot.
If I use the manual settings, it still does the same thing, regardless of what f number I choose, but I can get it to take viewable images by altering the shutter speed.
I have tried taping the aperture lever on the lens to the biggest aperture and it will then take images that can again be viewed.
I bought the camera recently from a well known auction site, it had been dropped by the previous owner which had resulted in a cracked LCD cover glass and the bayonet mount broken on the lens, both have been repaired by myself, but otherwise supposedly in good working order...but bought as seen, no returns!.
I get the !Error press shutter again! message sometimes on any of the settings (Auto,M,A,S), quickly switching the camera off and on again clears this, pressing the shutter again just takes pictures but doesn't clear the message.
I have tried the WD40 fix as suggested on the web but this hasn't really helped.
The auto-focus works ok, and when it takes viewable images they are lovely and clear.
From reading here and other sources, I can assume that it's probably the Aperture Control Unit that has probably gone faulty as a result of the dropping, and as the camera is way out of any warranty it's going to be an expensive Nikon repair, probably more than I paid for the camera.
My solution, if you guys think its possible, is to use an older lens, probably film lens, with manual aperture control and ignore the internal electronic control, using the camera on manual full time, which is why I bought a DSLR, I have an auto camera for happy snapping.
Any help and advice is greatly welcome....what lens options are available and maybe hints as to any fixes.