Quote Originally Posted by JLP View Post
I recently added a fourth lens to my kit and had to get a larger bag. I chose the Lowe Pro Flipside 400 and have not regretted.
It takes a little getting used to but it's main feature is that you can keep the waist strap on, take of the shoulder straps and swing the bag around in front of you. You access the insde of the bag from the back. Standing in water this is a huge advantage.

That said, i do not have a lens as long as the 250. my lenses are 40, 50, 80 and 150 a 503CW and 3 backs.
There is room for filters and small stuff in front of the bag and i have bought one of the lens attachments which holds my extra film rolls.
It is possible that one of the many lens attachments would hold your 250mm.
I have this bag too and I really like it. When solidly packed it can carry a lot of gear. Earlier this year I travelled with a three-lens Hasselblad kit (50, 80, 150mm), a three-lens EOS-1v kit, and a Wollensak Stereo 10, all in the Flipside 400. There was no room left for any significant accessories like flash units, etc, although I could still carry smaller stuff like filters, meter, film, etc. Although it carried all this gear the weight was something I'd rather not experience again for extended periods like that! Since I've been back I've been using the backpack as a one-camera kit bag and it's great. You'd have no trouble putting your kit in it I'm sure. One thing that particularly drew me to it, especially for travelling, was how the main compartment is accessed from the side that contacts your back. That's much more secure in my opinion. No low-life in a crowded train can unzip the backpack and steal a lens on the sly.

Having said all that, the only other backpack I own and can compare it to is a Micro-Trekker 200. It can fit my 3-lens Hassy kit with a few small accessories, but it would be too small for a four-lens kit.

The pouch in the top left of the photo is my light meter and the camera at the top of the photo is a Stereo Realist (I ended up taking the Wollensak Stereo 10 on the trip rather than this Realist though). The main flap has some storage space on the inside for thin items, and on the thief-accessible outside rear there is a larger storage space as well for miscellaneous items. Ignore the Canon gear and the Stereo Realist and you'll get an idea of what else you can fit in this backpack on top of my 3-lens 500C/M kit.