Aperture Matters

My fascination with aerial lenses has landed me with another large piece of glass.

This latest aquisition came from Stockton, CA, and is the venerable 900mm f8 lens.  This particular example does not have aperture blades or a shutter so it will need to be used wide open.  I will need to make a lens cap for it to function as a shutter.  From what I can gather, it should be able to project a usable field up to 8x10, possibly more.  I won't have the ability to use all of that since I have the 4x5.

To use this large piece of glass, I'll take advantage of the flange to mount it to a frame made of angle iron.  I'm planning to modify a Horseman 4x5 front standard to mount it.  I have one on order for parts for just this purpose.  

Given what needs to be done, it's unlikely that this will see first light before the end of the year.  

 Followup: The Horseman 4x5 bellows do not fit over the back of this lens.  Thus, I'm going to use the Toyo 160mm size bellows.  These will drop over the lens and allow the use of a rear standard for focusing and film holding.  I've got the bits on order to fabricate half of a camera.

Mounting the lens is going to be interesting.  The flange that is already on the lens is a wonderful thing, but I'm opting to re-use the rings from the Mak project.  These are 143mm rings that will need some shimming of the lens to properly grab the tube.  Tony has a metal roller and can help bend some shims to fit the proper size.    Just need to measure the thickness needed.  I think that 2mm will do the trick.

That flange may end up being a place where I can put some handles.

Lastly, the center of the lens once mounted will need to line up with the center of the ground glass.  The Toyo 45G will have a center that will be about 100 mm higher than the lens.  Once I get the rear standard in my hands I will be able to properly measure it.  The rings will need to be lifted by using some square tube stock.