Nikon D70S light meetering problem and focus issues?

[rac2873]

Hi I am new here but I have been hoping that someone is able to help me determine what the problem is.

I was in a indoor play area yesterday and I brought my 50mm 1.8 so I have a fast lens. I was trying to take pictures of my daughter and I had the ISO set to 400. I set the Fstop to 2.8 and the light meter said I was underexposed and in Aperture priority mode it suggested a speed of 1/15. I cranked up the ISO to 1000 and it went up to 1/30. Now I am not an expert but with that speed and ISO I should have been overexposed becuase there was plenty of light. I tried 1.8 but it was still about 1/80 and that is way to slow to capture of little girl running around. Also I set the focus bracket on my daughter and somehow my wife is in focus and my daughter is not.

My concern is that this camera is giving my incorrect light readings. I cannot shoot fast enough indoors to capture motion even with a fast lens. a 50 1.8 at ISO 400 or 800 should have givien me plenty of speed to capture the action but instead I get blurry motion trails and out of focus images if I use their recomendations.

I know this post seems a bit jumbled but this is the first time I have ever posted about cameras so I am a little out of practice on how to compose posts.

Hope someone has some insight on what could be wrong with my camera.

I tired auto ISO but that suggest 1600 and that is way to grainy for me to use those photos.

Thanks.

Rich

 

[rac2873]

Oh well I am going to call Nikon and probably have to pay for out of warranty repairs.

 

[KmH]

ISO 800 is only 1 stop more than ISO 400. 1/30 is also 1 stop more of shutter speed than 1/15. That's why the change from ISO 400 to ISO 800 got you just one more stop of shutter speed to 1/30.

The next higher stop of ISO above ISO 800, is ISO 1600, not ISO 1000. ISO 800 to ISO 1000 is only 1/3 of a full stop.

ISO 1600 would have allowed a shutter speed of 1/60, a stop more shutter speed over 1/30, but still not a fast enough shutter speed to stop a little girl at play.

The next higher stop of ISO over ISO 1600 is ISO 3200. Notice the doubeling of the numbers. That is what a full 'stop' is, a doubeling or a halving. ISO 3200 would have given you a shutter speed of 1/120, and ISO 6400 would give you a shutter speed of 1/240.

There is likely nothing wrong with your camera. In all honesty, it sounds more like you don't yet have a good understanding of exposure basics. You didn't mention which of the 3 metering modes you were using either.

You could have put up the pop up flash, put it in manual mode, and added light to the scene. The flash of light has a short enough duration to take over the motion stopping capability of shutter speed. Plus you can then use the shutter speed to control the ambient light exposure separately from the flash exposure, which is controlled by the lens aperture.