I have J-3s and J-8s love them and use them all the time. Nevertheless I have never seen a Soviet copy that equaled the f2/50mm or f1.5/50mm Sonnar - this of course is entirely my own opinion.. Even among the real Sonnars there are good and better examples - best to try the lens if you can. The f1.5/50mm tends to be the more desirable for a few reasons but I have at least one f2/50mm Sonnar that is extraordinary.
I'm not quite certain there is a useful distinction between the Opton and the late CZ f1.5/50mm Sonnar. True there is that separation problem but Henry Scherer often can fix that - I bought one with separation for about $50 and even though Henry couldn't do a perfect job (and charged me only $25 as a result) the lens is outstanding. Opton lenses have their share of problems as the factory workers were not particularly skilled or experienced in the early days (chipped or decentered elements are not unknown) and there were a number of design changes to the internal construction to solve deficiencies in holding the elements in place and/or the disassembly of the lens.
If you add to the cost an overhaul by Henry (he frequently can be persuaded to do lens work in a few weeks rather than years), Ken Ruth or Dan Goldberg (DAG) you will have a cleaned, centered, lubes and properly collimated lens - only then can you appreciate the full potential of the classic lenses.
Aside from the 21mm Biogon which I have a long standing love affair with (partially romanticism but hell that's part of the fun of classic cameras) the post-war West German 35mm Biogon is a real winner - noticeably better than the pre-war and the CZJ postwar coated version of the prewar (and that was a great lens as is the J-12) In fact I would buy a J-12 to hold me until I could get the West German lens. BTW I had dissappointing results with both a white early J-12 and the late black one until someone told me to use the white one on early Kievs and the black ones on later - whether true or not it worked very well for me and both lenses are really quite good.
The Helios is a double gauss formula which is basiclly a copy of the CZJ Biotar; a good modernish lens somewhat susceptible to flair - great value for the money but without the special visual character of the Sonnar. If you like the Sonnar go for it, if you prefer a Summicron the Helios may be for you. At the price of the Helios you can afford to use both.
Michael
