Richard asked how similiar these 2 lenses are. Thus I took a Biotar and a Helios and took similiar pictures, all wide open (on Nex 6). Do not expect a real comparison, you´ll see, that they are very similiar in drawing and bokeh.
First the 2 lenses, then samples
Allways the first picture is done with Biotar and the second one with Helios.