[Zipper] I purchased both the Lowe Pro 600 AW III backpack as well as the Alta Sky 66 to see which I liked better.� I tested them with my Canon 1DXII and Canon 600mm f/4 II lens, a Really Right Stuff carbon fiber tripod with Wimberly gimbal, and a carbon fiber mono pod. �

Pros: The Lowepro is designed well to carry the weight of the above listed gear. The pack feels stable and the hip belt is well designed to transfer the weight from shoulders to the hips for an all-day trek. The adjustable strap system allowed me to properly set it up for my 6'-1" body.� The Alta Sky 66 could not be adjusted long enough to accommodate my height comfortably and its hip belts were too light to transfer the load of all this gear well. It certainly protects the gear well with its ample padding and straps. There are plenty of loops and straps on the sides and hip belt to allow attaching lens cases or anything else.� The tripod and monopod strapped securely to the sides. I can store the camera with both the 600mm and a 2x teleconverter attached without issue.� On the Alta Sky, I needed to remove the 2x and store it in the pack separately.

Cons: The cons were not serious, but it is not styled as nicely as� the Alta Sky 66. This Lowepro looks a little nerdy sticking up like a monolith and would benefit from something to break up the smooth zipper flap.� I also wish it was optionally possible to attach the tripod on the rear instead of the side like the Alta Sky, but this is not a big issue either. �

Conclusion: For me the Lowepro was the only reasonable option because of my height and the weight/size of my gear.� I am quite happy with it.� If I had a 400mm f/2.8 setup and was 5'-10" I might chose the Alta Sky.

[Zipper] I use this backpack with my Canon EF 500mm, with the 1.4x extender attached. Before I owned this bag, I would carry the lens in a smaller backpack with the camera body and the tripod in two other bags (3 in total). Needless to stay, it was an awkward and frustrating arrangement. With this bag, the whole setup can be easily carry within one secure place. The quality is top notch and with correct usage, I hardly ever feel the weight of the equipment. Do note though that this is way too big to ever be allowed as carryon on a plane

[Backpack Straps] I've been looking for a pack to carry my 600 f/4 with TC and camera attached for a while. I've tried many others but feel this Lowepro works the best for me! The lens feels completely secure when hiking and doesn't move around at all. I also strap my Gitzo monopod w/ Wimberley gimbal head and the whole setup weighs 22lbs (including water). Very easy for long hikes! For size reference, I'm loading a Sony 600mm f/4 + 1.4x TC + Sony a9ii with battery grip. When stored in the pack I keep the lens hood reversed without the hood cover so it's still very fast to pull out and fire off some shots! When the lens is in the pack I have approx. 3-4 from the camera to the top of the pack.

[Backpack Straps] This is an amazing backpack, its massive but very comfortable. I've used some larger backpacking backpacks in the past, and this bag has the same adjustments as well as comforts as those backpacks. I was also able to fit my 800mm sigma with a 1.4x telephoto and a 1DX! I highly recommend this for anyone looking to transport a large telephoto lens setup in a very comfortable, yet sturdy backpack. I do not believe this will fit on any carry-on for planes.

[Empty] Z9 with 800mm 6.3 attached fits great! simply the best transport case for this combination.

[Empty] I purchased the Lens Trekker 600 AW III to carry a Nikon 600 f/4 lens with body attached and it fits perfectly. The backpack is very sturdy and has great padding to protect the lens. Additional adjustable support pads hold the lens securely in place when transporting. The shoulder harness system is adjustable for a perfect fit and the waist belt has great padding and helps tremendously to support the weight and ease the load on the shoulders. There is enough room above the lens with body to carry another body and lens on the padded shelf.

[Empty] Ordered another as my wifes dog chewed the shoulder straps off of my brand sew pack before I had a opportunity to use it. On to the new pack, it's excelent quality, very comfortable with my D4s & 600 f/4. Onlu complaint it should be about 6 taller so I don't have to reverse the len's hood. Also, the new pack is now always behind closed door's. BAD DOG

[Zipper] Fit my D6 with 600 mm F4 and tc works well

[Zipper] Each version of this bag gets an upgrade. This upgrade is significant in length and comfort. A small pouch on belt for quick access. I have 3 of these bags, this last version is the best. Hiking in or packing into the car this bag will keep your lenses secure even with extender and camera attached. Camera can be detached or an extra body stored on top. If you have a 600 or 800 lens this bag will solve your transportation concerns.

[Empty] I recently purchased this bag for a backcountry hike into Denali National Park. It was perfect for my tamron 150-600mmm lens attached to my camera body as well as my carbon fiber tripod and gimbel head and my stool. There was room for necessary accessories, my rain gear and trail food. The best part was the adjustable straps and load stabilization. I wish it held a few lenses inside but my waterproof lens cases clip on just fine for my macro lenses. I hike a lot and this will be a great addition to my gear.