Wide Open -- NEX-5 & Switar 50mm f1.4 @ f1.4. Click for larger.
Both AR and RX are c-mount lenses. You would think that a c-mount lens is a c-mount lens. It's a standard, right? Well, if everyone makes everything to the exact standard, the world will be a much nicer place. Alas, the AR and RX lenses share the same mount, but different lens to film register. My Switar 50mm f1.4 can focus to about 3 meters wide open, and the Switar 25mm f1.5 is about the same. They are still usable, just not to infinity. Until someone makes a special c-mount to accommodate the difference, these AR lenses will be much less useful than they really should be.
Another one wide open -- NEX-5 & Switar 50mm f1.4. Click to see larger.
I wouldn't feel so bad if these lenses are mediocre, but they are nice little lenses, especially the 50mm f1.4. I really like the bokeh of this lens, although it may be a bit weird to some. The image quality reminds me of the Switar 25mm f1.4 RX that I used to have, and still regret to this day that I sold it. The 25mm f1.4 has very severe vignetting even on the Panasonic G1, but the 50mm f1.4 has only very slight vignetting on the NEX-5.
Re-post, because this is one of my fav -- NEX-5 & Switar 50mm f1.4. Click for larger.
I am sure I will continue to make this kinds of mistakes in the future. There are just so much that I don't know. Was it Socrates that said "The more I learn, the more I learn how little I know"? Well, that about sums it all up.