Ernostar was derived from the equally famous Triplet design, and in turn, the Sonnar design was derived from Ernostar. The Canon EF 135mm f2L lens that I and many love, is a derivative of the Ernostar. With this history, I had high expectations when I tried out the Ernostar 110mm f1.9 projection lens.
B&L Cinephor 120mm f1.9 on the left, Zeiss Ikon Ernostar 110mm f1.9 on the right.
The Ernostar 110mm f1.9 has nice multi-coating.
This is a very large lens, similar to size and weight as the B&L Super Cinephor. It has very beautiful multi-coating, which is quite unusual for old projection lenses. However, the very short flange focal distance makes it hard to focus to infinity even on the Sony NEX-5N. I had to use a very short 12-17mm focus helicoid. In actual use, the lens performed better than the newer B&L 120mm f1.9. Purple fringing is surprisingly well controlled. It's almost as good as modern lenses.
Green -- NEX-5N & Zeiss Ikon Ernostar 110mm f1.9. Click for larger.
The lens is sharp with very good contrast. I would rate it excellent at its working aperture. If only I could stop it down a tiny bit, I am sure the sharpness will be even better. As is, it's completely usable but the thin depth of field makes it hard to focus. Again, the EVF helps a great deal here.
Bokeh -- NEX-5N & Zeiss Ikon Ernostar 110mm f1.9. Click for larger.