Since Kiron Lenses do not have a CPU built into the lens, they will not meter when mounted on your D90. The D90 does not support metering with non-CPU lenses. The lens can be used on the D90 though you must have the camera in Manual exposure mode and Manually set the ISO. If you want to use flash: built-in or in hotshoe, you must have the flash set in Manual flash mode as well. Good Luck and Enjoy your Nikons!