Photocraig

I have such a harness from the Film Daze by Tamarack. I think they're no longer in business. Essentially the harness is attached to the photographer over the head and both shoulders. The camera attached to vertical straps with pinch clips identical to their regular over the neck strap--identical to their regular strap. The chest cross piece has a mounted flexible rubber section with a hole in it able to stretch over the lens. This is easily slipped off for photo action and while engaged keeps the camera snugly close to the photographer's sternum. With my 70-300 lens I was able to turn the camera downward and have the base plate close to my chest with little interference. I have used this will backpacks, including a full sized external frame unit.

The downside is it looks goofy, like some sort of mono cup brassiere. However on a mountain hike with even a moderate sized lens, this harness kept the camera under control better than anything else I've seen.

I'd love to get a compatible neck strap so i can use the system again, someday. 'Cause I sure enough don't care about appearances.

Good luck on finding something similar. If you could attach your "holster" to a strap or band around your chest or on to a jacket or shirt, I think you could gain similar control. Otherwise, a vest might do ya.

mizzee Loc: Boston,Ma

BosStrap! Side attachment, great weight displacement. All day with my Nikon 70-200 and my Nikon d7000 in Bryce Canyon! No problem,no pain. Just do it!

jdubu Loc: San Jose, CA

I just got Op-Tech's newest version of the sling strap. I have the older sling straps and really use them. The new version has an extra slide clip that you can pull the end of the strap to shorten the sling, hugging the camera as close as you need, or loosen the clip for lengthening to bring the camera up for shooting.

Have used it for a few weeks now and it's definitely a keeper.

Dossile

I use Peak Design straps. Like them a lot. The DSL camera strap is like a seat belt and is extremely comfortable. My Micro 3/4 strap is much narrower. With either, I can wear it across my chest and comfortably swing it up to shoot. I like that I can carry across my chest like this without the camera hanging from the tripod screw-in.

Jimmy T Loc: Virginia

I really like the OP/Tech USA slings. They are really high quality, highly adjustable, reasonably priced and I have them on all three of my DSLR camera bodies. https://smile.amazon.com/OP-TECH-USA-Utility-Strap-Sling/dp/B003T0EYVE/ref=sr_1_3?s=electronics&ie=UTF8&qid=1529486598&sr=1-3&keywords=Op%2FTech+Sling&dpID=41DNVKiSQUL&preST=_SY300_QL70_&dpSrc=srch

LarryFitz Loc: Beacon NY

Cotton, out of Vancouver, makes a vest. Great for hiking, cameras is secure on my chest. This allows me to use my hiking sticks.

Jerrin1 Loc: Wolverhampton, England

Why not do what I do and use a Cotton Carrier or a Chinese copy. Both available from Amazon. I broke one of the carrier clips on my Chinese copy (entirely my fault) and replaced it with a genuine Cotton Carrier twin. Expensive but excellent. Both types hold cameras and lenses so secure that it is possible to run for a considerable distance without fear of a camera dropping off. All the weight is on your shoulders and the cameras are quickly removed by turning through 90 degrees. I wear mine for 7 - 8 hours a day over all types of terrain.

Grnway Loc: Manchester, NH

I also use them. Lots of options for how to carry. You can use as sling or traditional and can also use extra attachments to faste to backpack straps

jccash Loc: Longwood, Florida

I have a camera strap from ProMediaGear. They offer good products. They might even customize for you if you call them. Their setup is fantastic.

http://www.promediagear.com/

TJBNovember Loc: Long Island, New York

I've used OP-Tech straps on all my SLR's and now My DSLR's since the early 90's if you can't find something browsing their site I'd be surprised.

https://optechusa.com/products.html?p=3

jerryc41 Loc: Catskill Mts of NY

Two problems: finding a camera store; finding a camera store with an assortment of straps.

PMW603

I’m over 60, short and have a thin neck and shoulders and have found the Black Rapid shoulder strap meets my needs for hiking with my Canon 7DM2 + Canon 100-400mm L lens = 5 lbs. It has slide clips that lock into place while walking so it doesn’t slide around. It connects to the lens tripod mount preferably because the weight is too much to carry from the camera mount. I have severe neck problems and this has pretty much solved my camera carrying needs. I also carry Swarovski bins on a harness over the Black Rapid camera shoulder strap and the two work well together.

willy6419

check out the Cotton Carrier. It's a vest that has quick, secure attachment with a safety strap and a quick release holding strap that keeps your unit securely in front of you.

miked46 Loc: Winter Springs, Florida

look into BOSSTRAP

tradio Loc: Oxford, Ohio

I'm sure others are adjustable too but, I like the Peak Design slide. Quick on and off of the camera and fully adjustable. It also has a wide strap to dissipate the weight.
I do not know if these are available in stores or not. but like has been said, you must try before you buy.