The cheapest solution is here:
I broke the common f1.4/25mm US$15 C-mount by fixing it.
I was trying to adjust the f-stop readout to my adapter
by loosening the one screw on the focus ring.
NOTE: Do not try this unless you want to build something of the resulting parts...
After "fixing" it, my lens was in two parts:
Optics and iris in the front part and the focusing mechanism [so called - it's an empty hole with grease, more or less]
in the lower piece with the actual c-mount thread.
The lower piece may be used for whatever optics parts you've got lying around and want to try through the c-mount adapter.
Mount the optics part to the adapter with a piece of bicycle inner tube - if you do it right you can still use the f-stop ring on the lens
(but normally the weirdest results comes with full aperture). If not - easy to change!
Focusing is done by pushing and pulling on the lens. The tilt'n shift is done by bending the assembly horizontally and/or vertically.
Below first two pics: What this beast looks like (sorry it's all dusty...)
Below last four pics: Some results from the first trial session
First picture with my new lens: [Tone Expansion] on front dial, 1/40th sec, f1.4, ISO400.
Note the weird vertical focus plane you get from bending tube sideways!
[Tone Expansion] on front dial, 0.4 sec at ISO400.
A couple close-ups of potted plants.
This is what I get when I don't push the lens inwards for infinity focus.
[Tone Expansion] on front dial, f1.4 and 1/30th sec at ISO400.
[Tone Expansion] on front dial, f1.4 and 1/50th sec at ISO400.
Total cost:
Broken lens US$ 0:- / Bicycle inner tube US$ 0:- (same story as with the lens for me - I tried to fix it...
. Alternately if you are not as clumsy as I -
get a free discarded tube from your local bicycle store) / Adapter to Q US$ 0:- (you already have it!)
You just can't beat that price....thanks/Erik