Backpack slr camera case on the market?

I like the flipside series by lowepro. A 200 or 300 should fit depending on the lens size. Kata also has good backpacks/

The major brands of camera backback bags are:

Clik

Kata

LowePro

Tamrac

Tenba

Think Tank

After owning bags of every brand listed above (except Kata), its my belief that Think Tank bags are the best - and I currently own 5 of them. They are professional grade bags, made with high-end materials, and have a lifetime warranty, which means for as long as you own the bag.

With all of the above brands, they make backpacks in the $150 range.

There are other brands, but the above brands are the ones I like and have owned.

After owning literally more than a dozen bags, I can offer some advice. Pack light. A bag large enough to hold everything is too heavy to carry comfortably. Consider a "day-bag" that only contains what your needs are for the day.

That is the way I have gone, and if I am going to a museum for instance, I take certain lenses, say a macro, a general all-purpose lens, and perhaps a fisheye and super wide angle. But if I am going to a baseball game, I won't need a macro but will need my f/2.8 telephoto.

So I just put what I need in the bag for the day.

And I don't need to carry battery chargers, cables, or other bulky stuff in a "day bag". Just an extra fully charged battery or two. Remember, in a day bag, you are only carrying stuff you will need immediately and leaving the other stuff home.

As a result, I am able to travel light, and am not bogged down by weight.

In addition to backpacks, many photographers prefer shoulder style bags as they can get to the contents easier. But that is hard on your shoulders if they get heavy (another reason to pack light).

A popular compromise these days are the so-called "sling" bags, where they wear like a backpack, but can be rotated to the front and accessed without taking the bag off. But this requires use of a single backpack strap, and here again, it it is too heavy, it cuts into the shoulders.

The best thing to do for a bag is to go to a local camera shop and see what they have. Try on several different kinds. Many stores will allow you to bring in your gear to "test fit" and see if it fits, and/or will allow you to return the bag if you find it is not the right one.

If you have a look on B&H Photo or similar you'll find hundreds of backpacks that suit your needs. Keep in mind though that no backpack is ever going to be big enough to carry every last piece of kit you may need, so you still need to think in advance before heading out on the road with your kit!

This is my bag but this company probably has a good selection of what you're looking for.

http://tamrac.com/5606.htm