sconcemike

I've ordered a bahtinov mask for the lens thanks almcl. Dont know why I didnt think of that before as they can be useful for a telescope. And thanks Peter for the advice, although I do try that each time - maybe my eyesight isn't quite good enough. Also the focus ring on the Tamron is not smooth so end up with a lot of movement.

I have a Nikon d3100 that I use with 3 lenses. My problem is focussing. My Samyang 14mm f2.8 will focus on the heavens if I turn the focus ring as far as possible. Great for sharp wide field. The kit 18-55mm is the same. However I have a Tamron 200mm that focusses beyond the stars and I can never tweak it except by pure luck. Does anyone have recommendations for a lens in that region (125-300mm?) where the infinity stop is at the stars? I also use a Star Adventurer for the longer exposures. Any thoughts greatly appreciated. Thanks.