Recently I tried my older Sigma 28-70 F2.8 EX on my Nikon D300. I bought this lens in 2001 so there may be some compatibility issues. Newer Sigma lenses come with DG or DF at the end. The main problem is underexposure. I have to set the camera to +1.3 to get reasonable exposed pictures. Every now and then exposure is way off. Especially when taking indoor sports pictures in less then ideal lighting situations. When using a newer Nikon lens exposure is alway spot on. I've used this lens on a D70s before and don't remember having these problems. Does anybody else have any experience with a D300 and older Sigma EX lenses?