The Topcor 10cm f2.8 is a beatifully built lens. Aperture ring has a locking mechanism which prevents accidental aperture change. You will have to depress a button in order to change the aperture. This button is located on the right of the lens and falls naturally on one of the fingers. It's a very well designed feature. The lens is very compact, about the same size as the 58mm f1.8. Minimum focus distance is about 1.2 meters, which is normal for lenses of that era.
The colors of the images taken with this lens seem very neutral, which is great for portraiture. Perhaps it was designed to be this way, as a 100mm lens is normally used for this purpose, though a maximum aperture of f2.8 seem rather slow. In terms of sharpness, the lens performs quite well even at f2.8, definitely OK for portrait. At f4, it has very high contrast and sharpness. So, initial impression is very favorable. Can't wait to put it through some more shooting sessions.
What a beauty! - Click for larger.
Red Umbrellas - Topcor 10cm f2.8 & Sony NEX-6. Click for larger.
Cotton Candies - Sony NEX-6 & Topcor 10cm f2.8 @ f2.8. Click for larger.
Megan - Sony NEX-6 & Topcor 10cm f2.8 @ f4