I recently acquired a Calumet/Xenophone behind-the-filter holder for my 8x10. It fits a 3" square gel filter. I have a 14.75" Caltar lens in an Ilex #5 shutter. Not a lot of documentation about mounting these filter holders. I've read everything from Velcro to double side tape to clipping it on. And I notice the three clips have screws but I have no idea what they're for. I was able to just use the tension of the three clips and fit it around the rear barrel of the lens inside the camera. It stays in there but doesn't feel quite right.

Also, having a filter inside the camera isn't really conducive to quick changes or adjustments. I do studio portrait work, and if I'm doing a lot of black and white, it can stay in there... I guess. Do people using these typically frame and focus through the filter? Mine is a Wratten #58 gel filter. Everything is green and not as bright in the ground glass.

Thank you.