JML 8¼" Process Lens - Open it Past f8?

[Ari]

Hi,
I have a JML process lens, 8¼" f8.
The aperture is mechanically controlled to not open beyond f8, but there's plenty of room for it to open past f8.
I've tried removing the three visible screws, but that doesn't change anything.
Anyone have advice on what to do so I can open the lens up?
Thanks in advance.

[LabRat]

First, look into the lens (with the elements in) and with the iris open, see if the iris matches the outer elements diameter... Often the iris will open more than the element's diameter, so check for that...

You might find that there is a stop screw somewhere, that can be removed, but realize that optically it may do weird things at more than f8, and don't expect it to perform better than >f8...

But for portrait work, or special effects, it may be nice IF you manage to unstop the iris to open fully... (That is, IF...)

Steve K

[Ari]

Thanks, Steve; I only saw three possible screws and none affected the diaphragm's ability to open past f8.
I don't plan on shooting the lens wider than f8, but it would be nice to have more light for composing and focusing.