My camera pack is getting too heavy for me. I'm not 21 years old anymore.......... I keep a camera pack mainly to travel and shoot natural landscapes. I intend to spend 6 weeks overseas next year and if recent half day hikes are indicitive, I need to shed some serious weight from my camera pack as my enjoyment has been somewhat diminished with mild fatigue a couple of times recently. My camera pack is ergonomically excellent and suits me well for hiking. I basically shoot with a D810+grip, 14-24/2.8, 24-70/2.8 and 70-200/2.8 and assorted (and very necessary filters / accessories etc). I can leave the battery grip and matching L plate out to save 502 grams but I need to shed a proper kilogram out of my kit to make a worthwhile difference - I have tested this by leaving out the 24-70/2.8 (@915 grams) for my most recent part day photo trip and finding the lighter pack a delight to lug like old times. The 14-24, is a brick, but it is also a non negotiable item - it is my favourite lens and I use it plenty often enough. The obvious 24-70/2.8 lightweight replacement is the 24-85 variable aperture VR lens which I have already used with the D810 for 6 months and not particularly liked my results at the wider end, nor could I get on with it's VR. This leaves the 70-200/2.8 I have the first version - classic Nikkor lens, I love it, I have a good copy and it's delightful bokeh often simply makes my day. I can live with the light fall off and lack of extreme edge sharpness on FX etc but the general crispness of this lens from wide open and it's OOF rendering is superb. But it's a space hog in my pack and my copy weighs 1521 grams.......... The new 70-200mm f/4 is said to weigh circa 850 grams which is (approx.) 670 grams lighter and a great deal shorter which would be ideal for my pack as the current /2.8 lens imposes itself into the next pouch a little making it a bit tight to fit in and remove from the pack - esp. when in a hurry to switch lenses. 670 grams is a substantial weight saving and coupled with the battery grip's 500 grams it will indeed make a considerably lighter pack weight. However, most of my hand held shots taken with the f/2.8 are with an f/3.2 to f/5.0 aperture. My hand held technique + D810 sensor really dictates that I use the 70-200 only lightly to moderately stopped down from wide open. I do not find the VR on my 70-200 older very good with ultra slow shutter speecs (ie < 1/125th) - often I have a better 'keeper' rate for slow shutter stuff without VR - for me I find VR on this lens better around 1/250th, when, in still air, I can handhold it steady without VR anyway. My main questions are :- a) To those have used both f/2.8 and f/4 versions - how does the bokeh compare on the f/4? b) Is the VR on the f/4 version a significant improvement over the older 70-200f/2.8 version? c) How crisp is the f/4 when it's wide open or stopped down to f/4.5 and f/5 is it in the same league as the f/2.8 for unless I can make the newer VR version work for me I'm likely to be using the f/4 lens as a hand held proposition set wide open or stopped down a notch or two. Any experiences, advice most welcome.