Instruction: Extract information from the supporting document to answer the given question.

Input:
Question: Can you access a DSLR with a lens (about the size of the kit lens) from the side zipper while walking with the backpack on at least one shoulder?
Document: I own numerous Think Tank products, and like all the others, this one is high quality, thoughtfully designed and overall, a great buy.Compared to the Think Tank "Glass Taxi" (which I also own), this one is similar but perhaps 50% larger inside, with an additional compartment giving you room for a laptop. This backpack fits a pro-sized DSLR with a large, heavy zoom lens attached in the middle compartment, and then numerous other lenses and accessories along the edge compartments.
The excellent padding, and believe me I'm glad it's there, doesn't compress and retains it's boxy shape. While I never felt out of place and like an obvious photographer with so much gear on my back when I used this for just day trips for personal photography in Sydney and Tokyo, I wish I had a smaller bag to just carry one camera and lens, but alas that is the compromise of travel! On those days I did appreciate the stretchy side pockets to slip in a water bottle!
I wanted a backpack type bag for my camera gear and I looked and looked online to try and figure which one to get. I had a few requirements.1 Be able to leave my 70-200 2.8 Sigma lens on the Canon Rebel XTI Body2 Carry my other lenses and chargers3 Have room for 17inch laptop4 Carry a tripod5 Fit under the seat on an airplane6 Have a waist strap7 Fit my video camera (HVR-A1U) and chargers and cables8 Be under $200This bag is all that and more.
Over the years, I've collected a closet full of bags, but never one that could carry everything comfortably. Until I purchased this backpack about 6 months ago.PROS:* Comfortable - I wore this on my back for three consecutive 12 hour days during an event (FYI: I'm 6'3", 175lbs, with a 33" waist). Thanks to the awesome shoulder straps and waist belt, it felt like 25 pound pillow.
I needed something to hold my gear and laptop (15&#34; MacBook Pro) and still be comfortable to carry *and* allow easy access to my gear. Enter the Think Tank Street Walker Hard Drive. Small enough to carry onto flights, roomy enough to hold two bodies with large lenses attached plus extra lenses, or one body and a dozen or so lenses. The backpack style straps are very comfortable even with the bag fully loaded.
They're made in a way that holds lens cleaning pens, pens, clothes, memory card holders, anything of that nature. Side pockets come in handy as well for keys or anything of that nature.Overall, made tough and roomy. I love it.
The one thing I wish it had is a handle on the side and not just the top. But that's a very minor nitpick. I love the way the bag stands up on its own. The zippers are strong and secure, yet open and close easily. Think Tank definitely got it right with this one.
My wife and I each use one of these as our carry-on bag for airline travel. They've been around the world and keep asking for more. Because they're so light weight, I can pack it full of gear and still meet carry-on restrictions. Though the bag isn't rated for it I can put my 600/f4 in one. My MacBook Pro fits well inside the zipper pouch. I don't even know it's there. All the pouches are great.
This backpack is awesome! There is tons of room, lots of side pockets, and many awesome features. I can fit my 7D, 24-70L, 100Lmm IS Macro, 70-200L IS II all in the bag plus a lot more. I also have my 580 EX II in it as well. I can fit the 70-200 with the hood on NOT Reversed and fit all of my other gear.
After I finally bought the Canon 5D Mark II with the 24mm-105mm lens I always wanted along with a 70-200m f/2.8 lens, it was time to buy a good backpack so I could take my gear on the road. I read every review I could find and even visited a couple of local stores. I narrowed it down to four different models all made by different manufacturers (Think Tank, Kata, Lowepro and Tamrac).
Answer: It's not designed as a quick draw bag. It has no side or compartment zippers. Its set up like a normal backpack. It's meant for transporting a lot of gear, a lot of weight safely and organized. So I'm sure could manage too do that if you set the zippers and angled the camera right. But I doubt it would the most comfortable thing. For something carry less and be able take out and use on the fly. I recommend think tanks turnstyle bags. Yours sacrificing most of the room. But it holds all you could need for day too day non professional use.