I used Sincere Sheep Kiellian Farm Blend, in Fustic/Indigo, left over from the Talon Warmers. It's wonderful yarn but I didn't have enough left to make another garment, so I decided to utilize its cushiness to protect my camera. The weight of the yarn is on the bulky side of worsted, I would say.
I used US size 9 needles and got 16.5 stitches in 4" in stockinette.
My camera is a Kodak Z740, and is awesome but has kind of boxy dimensions (3.5" x 3.5" x 4") so it's hard to find a case for it. I have a case that's about twice as big as it needs to be, but I wanted a smaller pouch so that I could slip the camera in my purse and not carry two bags.
Cast on 15 stitches. Knit in stockinette stitch until the piece is 14.75" long. On a right-side row, K7, bind off 2, K6. Turn. P6, cast on 2 using the single cast on, P7. This gives you a buttonhole. I haven't sewn on a button yet, but hey, I wanted to give myself the option. Continue knitting in stockinette until the piece is 15.5" long, then bind off.
Now make two shorter side panels. Cast on 15 stitches. Knit in stockinette stitch for 4". Bind off. Repeat.
Now just sew it together. Take one long edge of the long piece, and starting at the end that's furthest from the buttonhole, sew it to three edges of one of the smaller pieces, going long edge to short edge to long edge. Repeat by sewing the other long edge of the long piece to the other short piece. I just sewed it the way the Stitch 'n' Bitch book says to, using mattress stitch and "sewing a top edge to a side edge."
I was thinking at first that I would take a picture of how my camera fit in the pouch. It took me 24 hours to realize the problem with this idea. Yup, I'm getting my Ph.D. in genetics.