Joined: 01 Jun 2013
Location: Zagreb, Croatia
|Posted: Mon Mar 16, 2020 5:59 am Post subject: Black troika test drive
|After Lomo 3.7x 0.11 and Zeiss 6.3x 0.16 Semiplan objectives were discovered as fine performing objectives for photomicrography, I have measured their MTF resolution and CA, confirming above average performance.
Even before that I was wondering are there other exceptional lenses and objectives manufactured once in countries of the Eastern Bloc by companies such as PZO, Praktica, Meopta, Zeiss aus Jena, Lomo and others. After split up of those countries and dissolution of Soviet Union, many of those factories ceased their production while others transformed into private ventures, often changing their production lineup. I know there were many talented and capable optics designers there but limited resources often prevented them to produce the best possible stuff as presented on drawing boards.
During the last 16 years I have being testing hundreds of lenses using slanted edge MTF method. Sometimes products from behind an iron curtain appeared in my lab, usually showing just average performance but on some occasions surprised by very fine figures. After changing my interest as a photographer towards macro photography, naturally I was concentrated more on macro lenses in a lab as well. Due to their affordability and wide availability, I have bought dozens of Russian, Czech and former Eastern German lenses and objectives in a quest for some exceptional finds.
This thread describes 3 lenses made in former Soviet Union that made a way to my lab. Here is mystery lens called Telor 28mm f/2.0 that was bought as a part of strange contraption obviously a part of some larger device, Helios-33 35mm f/2.0 used in better movie cameras and finally Microplan 40mm f/4.5, a dedicated macro lens. Helios and Microplan are praised as high resolution 6 element designs measuring 340 and 420 lines (line pairs?) per millimetre respectively. Helios is said to be a copy of Carl Zeiss Planar design while Microplan 40 is actually one out of 4 micrography lens series followed by 65, 100 and 150mm models.
I started test session with Telor 2/28 which required separation from bulky external elements, measuring variable aperture values and making appropriate f-stop markings. This lens turned out to be a great disappointment. It has to be stopped down to f/5.6 in order to get the best out of it. Still, resolution didn’t exceed 1742/1325 LW/PH at 3.2x and 1300/1284 LW/PH at 3.8x. CA depending on tube lens used varied from 0.12 to 0.55, not bad but not exceptional either. Definitely, not the best spent $40!
In order to recover from a disappointment, I’ve followed with highly praised Microplan 40, confident I’ll see some remarkable MTF numbers. Well, it just didn’t happen. Declared 420 lp/mm translates into 140 lp/mm at 3x, well above 128 lp/mm Nyquist frequency of my 24 MP APS-C sensor. At 2000 LW/PH it was just half of that expected figure, with pretty poor CA. Of course, at 3.8x it was worse at just 1530/1580 LW/PH. Another disappointment, this time costing me much more.
Now I had only one Russian lens left that could make a day. And it fortunately did! If you check Helios-33 on Ebay you’ll see it comes in various shapes and sizes. Basically, it is all the same basic core expanded with different add-ons like rings, tubes, dials and threads. Mine came with ugly, clumsy and heavy rings serving as aperture and distance dials. The lens makes you imagine some Russian tank gun aiming device! ???? With add-ons removed, the lens eventually appeared pretty small and cute as seen on the shot above.
I have tested resolution and CA at f/2.0 to f/5.6, stacked to Agfa 4/107, Gretag 6/120 and Rodagon 5.6/150 tube lenses, reversed, providing 3x, 3.4x and 4.3x magnification. Best central resolution appeared at f/2.8 and the edge res was highest at f/4 with just a bit lower central value. So f/4 is obviously a hot spot. Resolution peaked at 2700 LW/PH at 3x and 2000 LW/PH at 4.3x (check the chart above). Unfortunately, CA is not that good, but easily curable in PP. So far I didn’t have much success with Capture One automatic CA correction but manual PS ACR plug-in tool works perfectly. While not the best ever, this lens does qualify for the top five in 3x to 4x range. Since it can be purchased for less than $100 including shipping, I consider it a good buy.
*According to Merriam-Webster dictionary, troika is a Russian vehicle drawn by three horses abreast.
All things are number - Pythagoras