You can buy a cheap zoom for your digital camera from APUG members. Digiral is bad and with a cheap bad zoom , it would be worse. Collect money and buy a newer autofocus electronic zoom from keh.com second hand and look at the adorama. When your electronic camera burned down , you stay without nothing. To own a Nikon FG and a Nikon Zoom is good luck , dont ruin it.
May be you can use a adapter and use your 70-210 with your digital also. Open a thread about it and get the answer. Adapters goes from so so 50 dollars.