Those were nice roof prism spotters back then, and they are still pretty good now. However, they use older technology. I don't think they are even phase coated (a modern necessity for roof prisms), so won't have super high levels of resolution. Leupold's newer 15-30X50 GR spotter is much better, and the Nikon ED50 is the best 50mm spotter available. It is in a league of its own in 50mm spotters.