John,
There is a chart on the JML website:
http://www.jmloptical.com/level2/index.aspx?pagename=ProductInfo/lenssystems_info.aspx  that you may find interesting. However, so many  similar focal length lenses are listed, it may be difficult to tell which lens you  have. Also, if your lenses are older, they may have been discontinued and not on this chart. I know there is one JML of about 8" FL that is supposed to have very wide coverage and is sought after by 8X10 users. From my reading of the chart , it appears the 209.5mm f11 versions have the greatest coverage. I imagine the figures given by JML are for the most critical graphic arts uses and for normal photo use the usable coverages may be larger. You will probably have to test the lenses you have to see what they acually can do.
    As far as opening the lenses up wider than f8, I've never thought of it, but it might work, at least for focusing. You would have limited depth of field at f4 (although if you are doing selective focus, that may be what you want), and some lenses do shift the plane of focus as they stop down, but that would be easy to check. If you are able to modify your lenses to open up wider, please let us know how it works.
Leonard
   
----- Original Message -----
Sent: Friday, January 10, 2003 5:15 PM
Subject: [Cameramakers] JML lenses

I have a JML 6 1/4 inch f 8 process lens and a JML 8 1/4 f 8  process lens.. They both appear to be extreem wide angle lenses .. Does any one know anything about these lenses , what they will cover  and what type of lens configuration is in them?  The iris stops about 1/2 way with a maximum apeture of F8 ... Has anyone modified one of these lenses to open larger than f 8?  It looks as if there is room to even get to f4
John Cremati

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