If you're unsure what LGM's are, refer to sale #1. Floyd and Cletus were really proud of getting this one for me. And they should be! It's gorgeous! This is a Wollensak Series A f5 Portrait Petzval of just over a 100 years ago. This one is the #4 12" for full plate format. Actually we would use it on 8X10 and let the corners go shadowy so we can show off the crazy Swirlies. What's really neat about the f5 series is you only lose 2/3 stop from the showboat lenses but the size is so much more manageable. This would fit on a 4X4 board if you wanted it to bad enough! The f4 lenses need a 6X6 board at least. This has a perfect smooth operating round aperture. Aperture is the old US style. 2 4 8 16 32 64 etc. f16 is the anchor. It's the same in both systems. So you have to count stops forward or backward from f16 to get to our modern equivalents. Hoping I don't have to put this on Eekbay. Prices have gone nutty for petzvals there. Give me $565 for this one and Floyd will be satisfied. Cletus thinks I should get twice that! Glass is gorgeous! You get to pay the shipping.