The original lens was longer. I cut the end so that it wont' hit the sensor. Click for larger.
With the lens mount. Lens mount has a 58-55mm step down ring, which will screw onto the helicoid. When the finished, I wrapped electrical tapes on the end part to prevent reflections hitting the sensor. Click for larger.
The whole 9 yards - with Helicoid and lens hood. Note how many step-up/step-down rings were used. Butt ugly but works.
How does it perform?
Marvelous! Optically, it reminds me of the Astro-Kino 65mm f1.5 projection lens, but sharper. It also does not exhibit as much back ground swirl as the Astro, but is still noticeable. The Ektanon 3 inch f2 is the sharpest projection lens I have used. It's insanely sharp at f2. The color fringing is also very well controlled. Very happy with what it can do, but like the Astro-Kino 65mm f1.5, it covers only 16mm projection film. In terms of image coverage, it actually has very little vignetting, but the corners are blurry, especially at infinity focus. As bad as this sounds, it's also one of its unique signatures: slightly swirling backgrounds, blurry corners with extremely sharp center. Below are some examples.
Tree Trunks - NEX-5N & Kodak Projection Ektanon 3 inch f2. Click for larger.
Tail Lights - NEX-5N & Kodak Projection Ektanon 3 inch f2. Click for larger.
Bokeh - NEX-5N & Kodak Projection Ektanon 3 inch f2.