I bought an Arca Swiss Series A 4x5 on an impulse last week, and it arrived yesterday. So far I'm very happy with the camera but I have a couple of questions. First of all the back looks like it should be a revolving back but as far as I can tell it doesn't rotate. The two pieces of the back were somehow separated in shipping at the point where it looks like it would rotate. I was able to put it back together without using much force but as far as I could tell there were no locking tabs or a ridge or anything to keep it together, it just seems like they press together and stay that way. Is this simply a non revolving back that looks like it should revolve? I know that I can simply remove the whole unit from the rear standard and flip it to either portrait or landscape orientation but if this is a revolving back I'd like to get it revolving again. My other question involves the ground glass. At some point a previous owner replaced it with what is simply a piece of clear glass with a thin piece of plastic only a few thousandths of an inch think underneath it with a grid pattern on it. This sheet of plastic has the overall look of frosted glass but I have no clue what it actually is. My question is did this camera originally have a piece of glass with a fresnel underneath it? Or was in just simply a sheet of frosted glass? And what should I buy and or use to get it back as close to original as possible. The current setup seems to be working fine but the glass is slightly small and there are small wooden shims under the clips that hold the glass in the frame, overall it just appears like it was cobbled together in a hurry. The thickness seems right as the two shots I've taken so far are sharp, I'm just not sure what to do about replacing it and keeping that spacing right. The first image is not of my particular camera but it shows the part of the back that I believe should rotate. The other two are of my camera. Thanks in advance for any help.