Since upgrading from a D5100 to the really nice D7100 I notice that pictures I have been taking are using high ISO even though I have set the camera up as I did on the D5100. Using AUTO ISO with a low of 100 to a high of 6400, and a shutter speed of 1/60. These worked well on the D5100 but the superior D7100 is having pictures with High ISO 2800 - 6400 where as I was generally around ISO 100 - 400 on the D5100. I tried manually and pictures come out dark when using lower ISO, with same lens on D5100 its fine.. ? Am I missing something here, I know the sensor on the D7100 is superior, but as there are more settings on the D7100 could there be one which is conflicting with another. Sorry for the long post but this is really bugging me..