Re: Eclair Cameras: DIY Lens test projector

[Mark <super16acl@aol.com>]

I took an old, tiny 1950s Kodak slide projector made of bakelite, (a 
plastic-looking material that fractures easily, and turns to powder when you cut it 
--- use a mask), sawed off the lens mount and added an ACL flange which can be 
finely adjusted to be 52mm from the test slide's emulsion (and of course in 
addition to C mount the flange can take any ACL adapters for Arri-S, B, PL etc), 
and installed a slide in a glass mount made from a piece of S-16 film with a 
S-16 test chart. This projector will easily tell you if your lens will cover 
Super 16.

By making a slide of one of those tiny airforce glass resolution test things 
sold by Edmund Sci, it should also act as an excellent resolution testing 
device. Also, it your distance from flange to slide emulsion surface is EXACTLY 
52mm, you can even check the distance markings  (collomation) of your lens!

All I did after sawing off the projector's lens mount was to take a small 
piece of 1/4" aluminum, (with  a hole bored for the lens to pass through the 
image), screwed in an ACL flange (a R-16 flange will do, since you can easily 
center up the C-mount hole to the slide), and then mounted it on the projector by 
drilling holes in the corners of the auminum piece, and attaching it to the 
projector will screws that have springs between the projector body and the 
aluminum piece so that the distance of 52mm from the test slide can be exactly set. 
(Or for absolute micro-perfection, one could, instead, add tiny worm-gear 
gizmos from Edumund Sci to adjust the flange distance). Clearly one must make 
sure that when removing the projector's lens mount, the front of the projector 
gets "dug into" enough so that when ther ACL flange on the aluminum is mounted, 
it will fall within a  52mm +/- range from the slide's emulsion.

It really is a no brainner, and can make life vastly easier, and more 
accurate (and less expensive) that shooting lots of tests.  (Yes, in the end film 
tests should be shot when you've narrowed down your options). It is a weekend 
project at most.

Mark.

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