Greetings. I am looking for a 300mm lens for 4x5 Black and White landscape and backpacking that isn't too heavy (like a 12 in. Ektar) or too, too expensive (like a 300 M Nikkor). What exactly is a 300mm Schneider Xenar lens? When googling this I often see references to Tele-Xenar, as well. Are Xenars and Tele Xenars two different things? Also, I'm assuming it's coverage is more than adequate for 4x5. Does anyone have any experience using these - are they decently sharp, coated, etc? Thank you LF brain trust, as always.