Easy access shoulder bag?

Like many (most?) of you, I've been through many bags on the quest for the perfect one. I mostly used a Think Tank Turnstyle 20 sling which allows easy access to the gear once spun around to my front, but some times I need more than it'll hold. I have a 5DIII and mostly L zooms, including the 70-200 f/2.8 II so they can be bulky.

I have a Think Tank Retro 30 and while its a well-built and comfortable bag, it has some usability issues. Being a messenger bag, the flap gets in the way. It takes two hands to push the bag away from my body and tuck the flap out of the way before I can access its contents. The bag is very soft and conforms to my body, which is good and contributes to the comfort, but this also means that it wants to collapse while I'm trying to stick a lens in it. This isn't such a problem while the bag it sitting on a hard surface, but its a major issue while I'm wearing it. I prefer to wear a bag across my body and can't always set it down to use it.

I've looked at the Tenba DNA series which has a zipper on top but I don't know if it'll help. I think the issue is more about the stiffness of the padding, especially dividers, needed to keep the lens slots open and easy to access. What bags should I look at?

I recently got a Mountainsmith Descent sling. It holds more than the TurnStyle 20, which I also looked at. The Descent can store a 100-400 or 70-200 mounted (hood reversed) and still have room for 1-2 other fat DSLR lenses and a couple of filters. It is well-made and thickly/stiffly padded and doesn't collapse. The outside pocket can fit thin items like a tablet. The image below shows the 100-400 in the deepest section. It came with 3 dividers as shown.

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Have you looked at the Peak Design Everyday Messenger bag? Even though it has a flap, there's a zipper at the top that lets you gain access to the inside without having to open the flap cover.

http://www.1kindphotog​raphy.com …eryday-messenger-bag.html
http://www.1kindphotog​raphy.com …day-messenger-13-bag.html

Also, their new Backpack lets you sling it to the front and lets you gain access to the contents inside from the side pockets

http://www.1kindphotog​raphy.com …-backpack-tote-sling.html

There's also the ThinkTank Speed Freak - http://www.1kindphotog​raphy.com …peed-freak-v20-waist.html

Thanks. I'd forgotten that that Peak messenger had a zipper in the flap.

Billingham.

Easy to access. No noise to open. Looks good. Keeps out the rain (the British know about rain).

I like the Hadley Pro, but there are plenty of bigger and smaller options.

Not the cheapest, but I was done buying shoulder bags after getting one.

I did get a belt system after it, though. Different application .

I have the Mountainsmith sling bag as well. Got it this year as a birthday present and i absolutely love it.