Without really trying, Your Humble Filmosaur seems to have accumulated an array of 50mm Soviet LTM lenses. My late model FED-2 came with the standard original equipment Industar-26 52/2.8. I then upgraded to a Jupiter-8 50/2, which I’ve been very happy with and which enjoyed a short stint as the regular lens on my Canon P before returning to the FED. The latest was a FED 50/3.5 (also referred to as the Industar-10) collapsible; this came with a free bonus Industar-50, which is very similar in design, but which has also been crudely converted into a fake Leica Elmar and has an extraordinary amount of damage to the front element (it looks like it was cleaned with sandpaper, maybe to make it look older or something).
Seeing this collection of lenses, clearly there was nothing for it but to do a comparison test. Three of the four are Tessar-derivatives – four elements in three groups – while the faster Jupiter is a Sonnar-type, with six elements in three groups. Soviet manufacturing was not noted for its rigorous quality control, and this plus the many decades that have passed since these lenses were built suggests that there is likely to be some variability in the images they produce. The J-8, I-26, and FED lenses appear to be in excellent shape; the I-50 clearly is not, but I decided to include it so I could see just how much of an effect a very rough front element (the rest of the glass is in good shape) would have on the images compared to similar lenses without damage.
All the lenses were cleaned thoroughly prior to testing, but no adjustments were made. The rangefinder on the FED body is calibrated to the focusing scale of the Jupiter-8; I have not noticed any particular inaccuracy in this calibration, but the lens has not been collimated to determine if the scale is perfectly accurate in relation to the optics. Even though I normally shoot with a lens hood, I left them off for this test in order to see what the lenses alone would do in varied lighting conditions. The camera was mounted on a tripod and the shutter actuated by cable release.
The film used for the test was Kentmere 100, developed in Caffenol; while a more modern fine-grained film might provide more definitive results, this is a film that I use often, and thus the results are more relevant to me than they might be with an unfamiliar emulsion. The images were scanned at 2400dpi. Aside from removal of any large dust particles or other debris from the scans (some minor dust may remain; I decided not to spot clean the scans too aggressively for fear of losing detail and muddling the results), no modifications were made.
The first shot was taken close up and wide open to see what the lenses would do at the extreme end of their respective capabilities. The lens was opened to maximum aperture and the shutter speed adjusted to correct the exposure. Focusing point was the cap of the mushroom, which was 1 meter from the camera. (Please click the photos for larger views.)
The FED shows good resolution and contrast across the area in focus, with reasonably pleasant, slightly swirly bokeh. It appears that the lens is front-focusing slightly compared with the others in this test.
The Industar-26 looks much like the FED, albeit with a slightly narrower depth-of-field with a maximum aperture of f/2.8 rather than f/3.5. Resolution is similar across the frame, while the bokeh is a bit softer and more neutral.
The fake Elmar/Industar-50 image is a little darker and lower contrast than the FED’s, which would be expected given the damage to the front element and consequent reduction in light transmission. Surprisingly, however, the resolution is not too far off the undamaged glass of the two other Tessar-types; the bokeh resembles that of the FED quite closely.
Last up is the Jupiter-8. Of course, being a full stop faster than the I-26 and almost two stops faster than the FED and the I-50, the DOF is much shallower. Nonetheless, resolution remains good in the focused area, showing a bit less contrast in the fine details than the I-26.
Wide open all four lenses performed fairly similarly, but the side-by-side comparison highlights some of their particular tendencies. In all the subsequent frames in this test the lenses will be set identically. This is the first in a series of posts, each of which will examine a single scene taken by these four lenses. Stay tuned for the next installment.