<p>I would like to keep a secondary camera in a bag, ready to go, with a hole in the bag for the camera lens to pop through and a tripod thread at the bottom. The tripod thread is not a problem but I'm having trouble with the filter ring hole.</p> <p>What I'd like is a sew-in filter ring for a 58mm lens, where I can stitch the ring into the bag and then screw in 58mm lenses directly in. Does such a product exist? Can it be made or repurposed from something else?</p>