Shadow

Can someone tell me why I get a shadow at the bottom of my pictures when I'm using my flash........

Thanks

It is the shadow of your lens when the flash fires.

yes, in the center

Are you using the pop up flash or hot shoe? What lens are you using when you get this?

pop up, 18-55mm and 18-200mm

I can see this happening with your 18-200 but it shouldnt be happening with your 18-55. I dont know if your pop up is shorter (leg when pop up) than mine on the D3100, but I have shot with my 55-300 with flash and not had barrel shadow.

Do you have the lens hood (sunshade) on the lens? If so, try removing it. The lens hood will often block part of the light be emitted by the pop-up flash (especially at wide-angle focal lengths) causing there to be a shadow at the bottom of the image.

Your shutter speed is set too fast for the flash.

The D90 flash sync speed is 1/200. If it's set @ anything faster, you'll get some black on the lower half of your photos because the shutter is closing too fast. Make sure you have the shutter set correctly, and also check your user manual on flash sync speed.

This should fix your problem.

Check your lens users manual. If flash vignetting is a problem it should comment on it. On my 18-105mm it says to remove the lens hood when using the flash or you will get a shadow, vignetting. Another way to cure that problem is to use an external flash with a bracket.

I believe it's the lens hood. The pop up flash doesn't get high enough to clear the hood.

Absolutely correct, John. The lens hood is the culprit here. That's why it's always best to use a hot shoe mounted flash, such as an SB-600 or -700 or -800 or even the expensive -900 models.

Just as an afterthought here, I should mention that if you're going to use the on board pop up flash, be prepared to change your camera batteries often. Pop up flashes are notorious for sucking a lot of juice out of batteries. Hot shoe mounted flashes carry their own batteries. Just something to remember.