I'm new to all this so forgive me if this is a dumb request for information. I have an N90s that works well with my old manual lenses. I just picked up a cheap Tamron 177d 28-80 3.5-5.6 AF so I could try out the AF functions before putting more money into the kit. For some reason the camera reads the max aperture at 5.6 and minimum at 32. The lens is 3.5 to 22. I don't see anything in the lens or camera literature that I could do differently. Am I just missing something simple, or is it a compatibility issue?