Bokeh of Soviet lenses
I tend to judge lenses not only by sharpness or contrast, but also by 'bokeh' (the rendering of out-of-focus areas). And I just wanted to do a comparisson of my lenses in this regard...
I did this test in June 2006, even before I bought my Bessa R. All shots in this comparisson were taken with my Zorki 4 camera with the Helios finder used to frame the 85 and 35 lenses (since the viewfinder of Zorki 4 only shows the view of a 50 lens). The lenses compared are Jupiter-8 (50/2), Industar-61 (50/2.8), Jupiter-9 (85/2) and Jupiter-12 (35/2.8). All the lenses are Soviet-made, but based on pre-war Zeiss designs. They are not copies, but the plans for those lenses were taken after the second world war as war reparations.
Thanks to Lubka for being a patient model... focussing with Zorki 4 sometimes takes a looong time ;)
Here are the results: (click image for larger version)
Jupiter-12 (35mm f/2.8)
The bokeh wide open at f/2.8 is nice and smooth and the image is quite soft in the corners with some vigneting. At f/5.6 the depth-of-field is so deep that there is almost no bokeh... but sharpness had much improved.
Jupiter-8 (50mm f/2)
Jupiter-8 is a Soviet 'Zeiss Sonnar'. This lens is my favourite. It's quite soft wide open, with very pleasing creamy bokeh, but surprisingly tack-sharp when stopped down. The contrast is lower wide open, but stopping down to f/2.5 helps a lot. The blackening of edges of lens elements isn't exactly the strongest point of Soviet lenses and stopping down to f/2.5 eliminates reflections from these surfaces. Also notice that wide open at f/2 out-of-focus highlights are rendered with stronger edges, but after stopping the aperture down to f/2.8 they are much smoother without the stronger edges... In my opinion f/2.5 or f/2.8 is the best f-stop for portraits with this lens.
Industar-61 (50mm f/2.8)
Industar-61 (just like the previous version called Industar-26) is a Soviet 'Zeiss Tessar'. It's sharp already wide open, with nice bokeh. The photo taken at f/2.8 shows how sharp it really is. It is said to be one of the sharpest Soviet lenses in LTM mount.
Jupiter-9 (85mm f/2)
The test photos show why short-tele lenses are considered best for portraits. The out-of-focus areas are rendered very smooth and creamy - an example of perfect bokeh. As the previous lenses, also Jupiter-9 is a Soviet 'Zeiss Sonnar'. It is known to be soft wide open, but very sharp when stopped down. My test photos proved this - soft at f/2, but tack-sharp at f/4. Beautiful...