The information on this forum is valuable and I respect the exchange of information. So please help me. There have been a number of “zoom” lens questions but here’s one that’s very specific. The big hike is this summer – the Muir Trail – some of the most spectacular scenery in the US. Space and weight are at a premium. I’ve got a great set up with the camera suspended from the backpack straps – not hanging from my neck and not packed away. This allows me to get a shot while on the trail, in a matter of seconds. I expect to take close ups of flowers, the animals that wander by and landscapes throughout the day. So here’s my objective – I only want to take one lens for the k20. Here are the choices that are already in the camera bag: Promaster 18-200 (great range, no lens creep, relatively small in size, not as sharp as other choices), Pentax 16-50 (great sharpness, good low light lens, not a great zoom range), Pentax 50-135 (great sharpness, good zoom range, good low light lens, a little big in physical size to be hanging from the backpack), Pentax 50 1.4 (great lens, excellent low light lens, no zoom). If there is another choice out there, please let me know what it is. I do have time to save pennies and go through the seat cushions between now and the end of the summer if that other great option exsists. This may be a one time chance and I want to make it right. Oh yea – I have plenty of cards and four batteries. Your thoughtful responses will be greatly appreciated.